Brad Abrams

Visual Studio Project Sample Loading Error: Assembly could not be loaded and will be ignored. Could not load file or assembly or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)

BradA — Sat, 12 Dec 2009 04:21:34 GMT

Some folks have mentioned to me that they are having trouble getting some of my samples to work. And in fact, just the other day, I ran into a problem getting my own samples to work. It turns out to be a problem with the way windows treats the sample that you down load.

Specifically, because you downloaded the sample from the internet, windows treats the sample as “untrusted” content. When you unzip untrusted content you get a directory full of untrusted content. Visual Studio is not so good and running untrusted content. Unfortunately, you get some really bad error messages like the one above.

Here is the error message from VB

Warning 1 Assembly 'C:\Users\brada\Desktop\MyApp.VB\MyApp.VB.Web\bin\MyApp.VB.Web.dll' could not be loaded and will be ignored.
Could not load file or assembly 'file:///C:\Users\brada\Desktop\MyApp.VB\MyApp.VB.Web\bin\MyApp.VB.Web.dll' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515) MyApp.VB

And here is the message from C#:

Warning 1 Assembly 'C:\Users\brada\Desktop\MyApp.Starter\MyApp.Web\bin\MyApp.Web.dll' could not be loaded and will be ignored.
Could not load file or assembly 'file:///C:\Users\brada\Desktop\MyApp.Starter\MyApp.Web\bin\MyApp.Web.dll' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515) MyApp

Notice these are warnings, so if you are only looking at errors, you will be even more confused.

There is at least a good warning when the project is being loaded. I am not sure why you are giving the option to continue here, because there are very few projects that will just work in the semi-trusted way. If you see this, hit cancel and fix the issue first.

Luckily fixing this is very easy. Just go back to the ZIP file you downloaded, select properties, then “unblock” the content.

Then extract the contents and rerun it. Everything should work fine.

Good luck!

Bytes by MSDN: Brad Abrams Interview with Billy Hollis: Silverlight 4, RIA Services and VS2010

BradA — Wed, 09 Dec 2009 19:06:00 GMT

Bytes by MSDN is doing a bunch of really interesting interviews with folks behind the technology.

In this interview I talked to Billy Hollis about Silverlight 4, RIA Services and VS2010.

Tune in with Brad Abrams and Billy Hollis as they discuss the latest Silverlight 4 release and the exciting new features and functionalities now available.

Video Downloads
WMV (Zip) | WMV | iPod | MP4 | 3GP | Zune | PSP

Audio Downloads
AAC | WMA | MP2 | MP3 | MP4

Enjoy!

Field Level Access with RIA Services

BradA — Tue, 08 Dec 2009 18:56:38 GMT

There are lots of reason you may need to customize the access to given fields within an entity. For example, HIPPA compliance requires that some data not be exposed to only employees with a need to know. It is often not sufficient to just NOT show the data in the Silverlight client, you need to not even send it over the wire.

This example works with Silverlight 4\RIA Services Beta and Visual Studio 2010 Beta2

I built a very simple RIA Services + Silverlight 4 example to show how this could be done. First, let’s run the app, then we can look at how we built it.

The first thing to notice is when we run it, no users are logged in, so we get no access to the data at all.

First, let’s log in as a Rocky, who is a jr. employee at our company. He should NOT have access to the social security numbers of employees, but the other information is good for him to be able to access.

As you can see, no SSNs are displayed.

Now, let’s log in as Billy, who is our HR Manager… As you can see, Billy has a need to know what the SSN is for most employees, so those are visible to him. But notice, even he can not see VP level personal information.

OK, now let’s look at how we implemented this. Really the key code is the domain service on which runs on the server:

  1:     [RequiresAuthentication]
  2:     [EnableClientAccess()]
  3:     public class EmployeesDomainService : LinqToEntitiesDomainService<NORTHWNDEntities>
  4:     {
  5: 
  6:         public IQueryable<Employee> GetEmployees()
  7:         {
  8:             foreach (var e in this.ObjectContext.Employees)
  9:             {
 10:                 if (!this.ServiceContext.User.IsInRole("HRManagers"))
 11:                 {
 12:                     e.SSN = null;
 13:                 }
 14:                 else if (e.Title.Contains("Vice President"))
 15:                 {
 16:                     e.SSN = null;
 17:                 }
 18:             }
 19:             return this.ObjectContext.Employees;
 20:         }
 21: 
 22:

In line 1, we mark this services are only accessible to users that are logged in.

In line 10, we are making sure that only the user making the request is in the role that enables them to have access to the SSN, if not, we null it out.

In line 14, we have a (lame) example to show accessing data on the entity to decide if the user should have access. In this case, even the HRManager can’t access the VP’s SSN.

Some notes on running the app:

Download the source code
Billy and Rocky’s passwords are “password1!”
Be sure the refresh the page after logging in or out
You can customize the roles by using the IIS Admin tool or the ASP.NET configuration properties on the Web solution

Enjoy!

PDC09 Talk: Building Amazing Business Applications with Silverlight 4, RIA Services and Visual Studio 2010 – Now in Visual Basic!!

BradA — Sat, 28 Nov 2009 06:13:00 GMT

I had a great time at my talk PDC2009 talk, but i was disappointed that I could not demo in both C# and VB… So here is the next best thing: A full play-by-play of the demo, but all in VB! Enjoy.

What you need to get started:

Visual Studio 2010 Beta2
Silverlight 4 Beta (now includes RIA Services)
Completed Solution (in VB)
Check out the slides and video from the talk

Starting Off

I am starting off with the new Business Application Template that gets installed with RIA Services.

This new template includes:

Pattern for page navigation
Log\Logout and new user registration support
Localizable
User settings
Shared Code

For this demo, I am going to used a customized version of the template..

After you create the project, you see we have a simple solution setup that follows the “RIA Application” pattern. That is one application that happens to span a client (Silverlight) and server (asp.net) tiers. These two are tied such that any change in the Silverlight client is reflected in the server project (a new XAP is placed in client bin) and appropriate changes in the server result in new functionality being exposed to the Silverlight client. To parts of the same application.

Exposing the Data

I started out with an Entity Framework model. RIA Services supports any DAL including Linq2Sql, NHibernate as well as DataSets and DataReader\Writer. But EF has made some great improvements in .NET 4, so I felt it was a good place to start.

So here is the EF model I created. Basically we have a set of restaurants, each of which has a set of plates they serve. A very simple model designed many to show off the concepts.

Then we need to place to write our business logic that controls how the Silverlight client can interact with this data. To do this create a new DomainService.

Then select the tables you want to expose:

Now, let’s look at our code for the DomainService…

 Imports MyApp.VB
Imports System
Imports System.Data
Imports System.Linq
Imports System.Web.DomainServices
Imports System.Web.Ria
Imports System.Web.DomainServices.Providers
 
 
<EnableClientAccess()> _
Public Class PlateViewDomainService
    Inherits LinqToEntitiesDomainService(Of DishViewEntities)
 
    Public Function GetRestaurants() As IQueryable(Of Restaurant)
        Return From r In ObjectContext.Restaurants
               Where r.City <> "Raligh"
               Order By r.ID
    End Function
 
 
End Class
 
 
 

In line 10 – we are enabling this service to be accessed from clients.. without this, the DomainService is only accessible from on the machine (for example for an ASP.NET hosted on the same machine).

In line 11: we are defining the DomainService – you should think of a DomainService as just a special kind of WCF Service.. one that is higher level and has all the right defaults set so that there is zero configuration needed. Of course the good news is that if you *need* to you can get access to the full richness of WCF and configure the services however you’d like.

In line 12: you see we are using the LinqToEntitiesDomainService. RIA Services supports any DAL including LinqToSql or NHibernate. Or what I think is very common is just POCO.. that is deriving from DomainService directly. See examples of these here…

In line 14: We are defining a Query method.. this is based on LINQ support added in VS2008. Here we define the business logic involved in return data to the client. When the framework calls this method, it will compose a LINQ query including paging, sorting, filtering from the client then execute it directly against the EF model which translate it into optimized TSQL code. So no big chunks of unused data are brought to the mid-tier or the client.

Consuming the data on the client

Now let’s switch over the client project and look at how we consume this.

in Views\Home.xaml we have a very simple page with just a DataGrid defined.

 <data:DataGrid AutoGenerateColumns="True"
               Name="dataGrid1"
               Height="456"
               Width="618" />
 
 

now let’s flip over to codebhind..

Notice we have a MyApp.Web namespace available on the client. Notice that is the same namespace we defined our DomainService in..

So, let’s create a local context for accessing our DomainService. First thing you will notice is that VS2010 Intellisense makes it very easy to find what we want.. it now matches on any part of the class name.. So just typing “domainc” narrows our options to the right one..

 Dim context = New PlateViewDomainContext()
dataGrid1.ItemsSource = context.Restaurants
 
context.Load(context.GetRestaurantsQuery())

In line 2, notice there is a property on context called Restaurants. How did we get that there? Well, there is a query method defined on the DomainService returning a type of type Restaurant. This gives us a very clean way to do databinding. Notice this call is actually happening async, but we don’t have to deal with any of that complexity. No event handlers, callbacks, etc.

In line 4, while the whole point of RIA Services is to make n-tier development as easy as two-tier development that most of us are used to, we want to make sure the applications that are created are well behaved. So part of this is we want to be explicit when a network call is being made.. this is not transparent remoting. Network calls must be explicit. In this line we are mentioning which query method to use as you might define more than one for the same type with different logic.

Now we run it..

This is very cool and simple. But in a real world case, i am guessing you have more than 20 records… sometimes you might have 100s, or thousands or more. You can’t just send all those back to the client. Let’s see how you can implement paging and look at some of the new design time features in VS2010 as well.

RIA Services support in Visual Studio 2010

Let’s delete that code we just wrote and flip over to the design surface and delete that datagrid.

Drop down the DataSources window (you may need to look under the Data menu for “Show Data Sources”

If you are familiar with WinForms or WPF development, this will look at least somewhat familiar to you. Notice our DishViewDomainContext is listed there with a table called Restaurant. Notice this is exactly what we saw in the code above because this window is driven off that same DomainContext.

Dropping down the options on Restaurant, we see we have a number of options for different controls that can be used to view this data… of course this is extensible and we expect 3rd party as well as your custom controls to work here. Next see the query method here that is checked. That lists all the available options for query methods that return Restaurant.

Now if we expand the view on Restaurant, we see all the data member we have exposed. This view gives us a chance to change how each data member will be rendered. Notice I have turned off the ID and changed the Imagepath to an Image control. Again this is an extensible and we expect 3rd party controls to plug in here nicely.

Now, drag and drop Restaurant onto the form and we get some UI

And for you Xaml heads that want to know what really happens… Two things. First if the DomainDataSource is not already created, one is created for you.

 <riaControls:DomainDataSource AutoLoad="True"
                              Height="0"
                              Name="RestaurantDomainDataSource"
                              QueryName="GetRestaurantsQuery"
                              Width="0">
    <riaControls:DomainDataSource.DomainContext>
        <my:PlateViewDomainContext />
    </riaControls:DomainDataSource.DomainContext>
</riaControls:DomainDataSource>
 
 

Finally, the DataGrid is created with a set of columns.

 <data:DataGrid AutoGenerateColumns="False"
               Height="200"
               HorizontalAlignment="Left"
               ItemsSource="{Binding ElementName=RestaurantDomainDataSource, Path=Data}"
               Margin="190,110,0,0"
               Name="RestaurantDataGrid"
               RowDetailsVisibilityMode="VisibleWhenSelected"
               VerticalAlignment="Top"
               Width="400">
    <data:DataGrid.Columns>
        <data:DataGridTextColumn x:Name="AddressColumn"
                                 Binding="{Binding Path=Address}"
                                 Header="Address"
                                 Width="SizeToHeader" />
 
 

Then setup a grid cell by click 4/5ths of the way down on the left grid adorner. Then select the grid, right click, select reset layout all.

.. add poof! VS automatically lays out the DataGrid to fill the cell just right.

Now, personally, I always like the Name column to come first. Let’s go fix that by using the DataGrid column designer. Right click on the DataGrid select properties then click on the Columns property..

In this designer you can control the order of columns and the layout, etc. I moved the image and name fields to the top.

Now, let’s add a DataPager such that we only download a manageable number of records at a time. From the toolbox, simply drag the datapager out.

We use our same trick to have VS auto layout the control Right click on it and select Reset Layout\All.

That is cool, but there is a big gap between the DataGrid and the DataPager.. I really want them to be right. This is easy to fix. Right click on the grid adorner and select “Auto”..

Perfect!

Now, we just need to wire this up to the same DataSource our DataGrid is using “connect-the-dots” databinding. Simply drag the Restaurant from the DataSources window on top of the DataGrid.

For you Xaml heads, you’ll be interested in the Xaml this creates..

 <data:DataPager Grid.Row="1"
                Name="DataPager1"
                PageSize="10"
                Source="{Binding ElementName=RestaurantDomainDataSource, Path=Data}" />
 
 

Notice, we don’t need to create a new DomainDataSource here… we will use the one that is already on the page.

Now, we are doing an async call.. so let’s drag a BusyIndicator from the new Silverlight 4 Toolkit.

We need to write up the IsBusy to the restaurantDomainDataSource.DomainContext.IsLoading… Luckily there is some nice databinding helper in VS2010. Select properties, then IsBusy, then DataBinding.

Again, for you Xaml heads, the Xaml that gets generated is pretty much what you’d expect.

 <controlsToolkit:BusyIndicator Height="83"
                               HorizontalAlignment="Left"
                               Margin="274,137,0,0"
                               Name="BusyIndicator1"
                               VerticalAlignment="Top"
                               Width="188"
                               IsBusy="{Binding ElementName=RestaurantDomainDataSource, Path=DomainContext.IsLoading}" />
 
 

Loading…

and once it is loaded…

Very cool… that was a very easy was to get your data. Page through it and notice that with each page we are going back all the way to the data tier to load more data. So you could just as easily do this on a dataset of million+ records. But what is more, is that sorting works as well and just as you’d expect. It doesn’t sort just the local data, it sorts the full dataset and it does it all way back onto the data tier and just pulls forward the page of data you need to display.

But our pictures are not showing up… let’s look at how we wire up the pictures. The reason they are not showing up is that our database returns just the simple name of the image, not the full path. This allows us to be flexible about the where the images are stored. The standard way to handle this is to write a value converter. Here is a simple example:

 Public Class ImagePathConverter
    Implements IValueConverter
 
    Function Convert(ByVal value As Object, ByVal targetType As Type, ByVal parameter As Object, ByVal culture As Globalization.CultureInfo) As Object _
        Implements IValueConverter.Convert
 
        Dim path As String
        path = value.ToString()
        path = path.Replace(":", "")
        path = path.Replace("/", "")
        path = path.Replace("\\", "")
        If path.Length > 100 Then
            path = path.Substring(0, 100)
        End If
        Return "http://hanselman.com/abrams/Images/Plates/" + path
 
    End Function
 
 

Now, let’s look at how we wire this converter to the UI. First, let’s use the Document Outline to drill through the visual tree to find the Image control.

Then we select the properties on the image and wire up this converter. If you have done this in Xaml directly before, you know it is hard to get right. VS2010 makes this very easy!

Oh, and for you Xaml heads… here is what VS created..

 <navigation:Page.Resources>
    <my:ImagePathConverter x:Key="ImagePathConverter1" />
</navigation:Page.Resources>
 
 

and

 <data:DataGridTemplateColumn x:Name="ImagePathColumn"
                             Header="Image Path"
                             Width="SizeToHeader">
    <data:DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <Image Source="{Binding Path=ImagePath, Converter={StaticResource ImagePathConverter1}}" />
        </DataTemplate>
    </data:DataGridTemplateColumn.CellTemplate>
</data:DataGridTemplateColumn>
 
 

Silverlight Navigation

Now let’s look at how we drill down and get the details associated with each of these records. I want to show this is a “web” way… So I’ll show how to create a deep link to a new page that will list just the plates for the restaurant you select.

First we add a bit of Xaml to add the link to the datagrid..

 <data:DataGrid.Columns>
        <data:DataGridTemplateColumn Header="">
            <data:DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Button Content="+"
                            Style="{StaticResource DetailsButtonStyle}"
                            Click="Button_Click"></Button>
                </DataTemplate>
            </data:DataGridTemplateColumn.CellTemplate>
        </data:DataGridTemplateColumn>
 
 

And to implement the button click handler…

 Private Sub Button_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
 
    Dim res As Restaurant
    res = RestaurantDomainDataSource.DataView.CurrentItem
 
    NavigationService.Navigate(New Uri("/Plates?restaurantId=" _
     & res.ID, UriKind.Relative))
End Sub
 

Here we are getting the currently selected Restaurant, then we cons up a new URL to the page “Plates”. We pass a query string parameter of restaurantId…

Now, let’s build out the Plates page that will the list of Plates for this restaurant. First let’s great a a Plates page. Let’s add a new Plates under the Views directory.

Now we need to define a query to return the Plates. Notice that only the data you select is exposed. So we get to go back to the server, to our DishViewDomainService and add a new query method.

 Public Function GetPlates() As IQueryable(Of Plate)
    Return From r In ObjectContext.Plates
           Order By r.ID
End Function
 

Now we go back to the client, and see your DataSources window now offers a new datasource: Plates.

Now, just as we saw above, I will drag and drop that data source onto the form and i get a nice datagrid alreayd wired up to a DomainDataSource.

Then, with a little formatting exactly as we saw above, we end up with…

And when we run it… First, you see the link we added to the list of Restaurants..

Clicking on anyone of them navigates us to our Plates page we just built.

Customized Data Access

This is cool, but notice we are actually returning *all* the plates, not just the plates from the restaurant selected. To address this first we need modify our GetPlates() query method to take in a resource id.

 Public Function GetPlates(ByVal resId As Integer) As IQueryable(Of Plate)
    Return From r In ObjectContext.Plates
           Where r.RestaurantID = resId
           Order By r.ID
End Function
 
 

Now, back on the client, we just need to pass the query string param…

 Protected Overrides Sub OnNavigatedTo(ByVal e As System.Windows.Navigation.NavigationEventArgs)
    Dim param = New Parameter()
    param.ParameterName = "resId"
    param.Value = NavigationContext.QueryString("restaurantId")
 
    PlateDomainDataSource.QueryParameters.Add(param)
 
End Sub
 
 

Now, we run it and we get the just the plates for the restaurant we selected.

what’s more is we now have a deep link such that it works when I email, IM or tweet this link to my buddy who happens to run a different browser ;-)

Ok… now for a details view… Let’s do a bit more layout in the Plates.xaml. First, let’s split the form in half vertically to give us some cells to work in.

In the bottom left we will put the details view to allow us to edit this plate data. Let’s go back to the DataSources window and change the UI type to Details.

Dragging that Details onto the form… we get some great UI generation that we can go in and customize.

In particular, let’s format that Price textbox as a “currency”… using the new String Formatting support in Silverlight 4.

And again, for you Xaml heads… this created:

Text="{Binding Path=Price, Mode=TwoWay, ValidatesOnExceptions=true, NotifyOnValidationError=true, StringFormat=\{0:c\}}"

Now, let’s add an image to the other side. Simply drop an Image control on the form and select Reset Layout\All

Now we can easily change the image to be “Uniform”

Now we need to write up the binding here so that as selection changes, this image is update. Luckily, that is very easy to do. Simply drag and drop from the Data Sources window…

Then we need to wire up our converter just as we saw before..

Run it…

That looks great!

But when we try edit something, we get this error..

Editing Data

Ahh, that is a good point, we need to go back and explicitly define a Update method to our DomainService on the server.

 Public Sub UpdatePlate(ByVal currentPlate As Plate)
    currentPlate.NumberUpdates += 1
    Dim orginal = ChangeSet.GetOriginal(currentPlate)
    If orginal.Price <> currentPlate.Price Then
        ' add 1 dollar fee for changing price 
        currentPlate.Price += 1
    End If
    ObjectContext() _
        .AttachAsModified(currentPlate, orginal)
End Sub
 

In line 2, notice we take the NumberUpdates and increment by one. it is nice that we send the entry entity back and forth, so we can do entity level operations very easily.

Next in line 3, we pull out the original value.. .this is the plate instance as the client saw it before it was updated.

In line 4-7, we first check to see if the price has changed, if it has, we add a fee of one dollar for a price change.

Finally in line 8-9, we submit this change to the database.

Now we just need to drop a button on the form.

Then write some codebehind..

 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles Button1.Click
    PlateDomainDataSource.SubmitChanges()
End Sub
 
 

What this is going to do is find all the entities that are dirty (that have changes) and package them up and send them to the server.

Now notice if you make a change price to the data and hit submit the NumberUpdates goes up by one and the the price has the one dollar fee added.

Then submit.. NumberUpdates is now 63 and the price is $73.84..

Then if you set a breakpoint on the server, change two or three records on the client. Notice the breakpoint gets hit for each change. We are batching these changes to make an efficient communication pattern.

Great.. now let’s look at data validation.

We get some validation for free. for example Calorie Count is a int, if we put a string in, we get a stock error message.

If we want to customize this a bit more, we can go back to the server and specify our validation there. It is important to do it on the server because you want validation to happen on the client for good UI, but on the server for the tightest security. Following the DRY principle (Don’t Repeat Yourself) we have a single place to put this validation data that works on the client and the server.

 <Required(ErrorMessage:="Please provide a name")>
Public Name As String
 
Public NumberUpdates As Nullable(Of Integer)
 
<Range(0, 99)>
Public Price As Nullable(Of Decimal)
 
<RegularExpression("^http\://[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(/\S*)?$",
        ErrorMessage:="Please use standard Url format")>
Public Uri As String
 
 

The data validation attributes are a core part of .NET with ASP.NET Dynamic Data and ASP.NET MVC using the exact same model.

But what if they are not expressive enough for you? For example, say I have a custom validation I have for making sure the description is valid.. To do that, I can write some .NET code that executes on the server AND the client. Let’s see how to do that. First I create a class on the server..

Notice the name here PlateValidationRules.shared.cs…. the “.shared” part is important… it is what tells us that this code is meant to be on the client and the server.

In this case, i am saying a valid description is one that has 5 more more words

 Public Class PlateValidationRules
    Public Shared Function IsDescriptionValid(ByVal description As String) As ValidationResult
        If (description <> Nothing And description.Split().Length < 5) Then
            Dim vr = New ValidationResult("Valid descriptions must have 5 or more words.")
            Return vr
        End If
        Return ValidationResult.Success
    End Function
End Class
 

Then to wire this up to the description property…

 <CustomValidation(GetType(PlateValidationRules),
            "IsDescriptionValid")>
Public Description As String
 
 

Then running the app, we see all our validations…

Personalization and Authentication

Lots of times in business applications we are dealing with valuable data that we need to make sure the user is authentication before we return in. Luckily this is very easy to do with RIA Services. Let’s go back to our DomainServices on the server and add the RequiresAuthentication attribute.

 <RequiresAuthentication()>
<EnableClientAccess()>
Public Class PlateViewDomainService
    Inherits LinqToEntitiesDomainService(Of DishViewEntities)
 
 

Then when you run the application..

So let’s log in… I don’t have an account created yet, luckily the Business Application Template supports new user registration. All this is based on ASP.NET Authentication system that has been around sense ASP.NET 2.0.

Here we are creating a new user…

And now we get our data…

Now, that we have a user concept.. why don’t we add one more setting to let the user customize this page. So we edit the web.config file to add a BackgroundColor.

 <?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.web>
    <profile>
      <properties>
        <add name="FriendlyName" />
        <add name="BackgroundColor"/>
      </properties>
    </profile>
 
 

And we go into the User.cs class on the server and add our BackgroundColor.

 Partial Public Class User
    Inherits UserBase
    
    Private _FriendlyName As String
    Private _BackgroundColor As String
 
    Public Property FriendlyName() As String
        Get
            Return _FriendlyName
        End Get
        Set(ByVal value As String)
            _FriendlyName = value
        End Set
    End Property
 
    Public Property BackgroundColor() As String
        Get
            Return _BackgroundColor
        End Get
        Set(ByVal value As String)
            _BackgroundColor = value
        End Set
    End Property
 
 
 

Now, back on the client, let’s build out UI using the DataSources window just as we have seen above. But this time, I have created a very simple ColorPicker control in order to show that it is possible to use your own custom control.

Drag and drop that onto the form..

Then change the binding to be TwoWay using the databinding picker.

Then I think we need a nice header here with the User name in it. To so that, let’s add a TextBlock, set the fontsize to be big. Then do connect the dots databinding to write up to the user name.

Then let’s use the string format databinding to customize this a bit..

Next we put a Submit button.

 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles Button1.Click
    Dim context = WebContext.Current.Authentication
 
    UserDomainDataSource.SubmitChanges()
    AddHandler UserDomainDataSource.SubmittedChanges, AddressOf SubmittedChanges
 
End Sub
Private Sub SubmittedChanges(ByVal sender As Object, ByVal e As SubmittedChangesEventArgs)
    Dim context = WebContext.Current.Authentication
    If Not context.IsBusy Then
        context.LoadUser()
    End If
End Sub
 

Now when we run it… we can modify the user settings.

The really cool part is that if the user goes to another machine and logs in, they get the exact same experience.

Summary

Wow, we have seen a lot here.. We walked through end-to-end how to build a Business Application in Silverlight with .NET RIA Services. We saw the query support, validating update, authorization and personalization as well as all the great new support in VS2010. Enjoy!

Silverlight and RIA Services: Implementing Search

BradA — Wed, 25 Nov 2009 19:11:51 GMT

Some of you likely noticed that my PDC09 demo included a stubbed out Search function that I didn’t really get to walkthrough during the talk. I thought I’d do a blog post showing how it is done.

To get started you need:

Visual Studio 2010 Beta 2
Silverlight 4 Beta (which includes RIA Services)

You can download the completed solution as well. and be sure to check out the full talk.

First let’s write a new method on the DomainService to return the search results. In this case I want to return any Plates who’s name matches (grouped by Restaurant) and any Restaurant who’s name matches.

 public IQueryable<Restaurant> SearchRestaurants(string term)
{
    //Find all plates that match, grouped by restaurant
    var restaurantPlatesList = this.ObjectContext.Restaurants
        .Where (r => r.Plates.Any (p=>p.Name.Contains(term)))
        .OrderBy(k => k.ID);
    foreach (var restaurant in restaurantPlatesList)
    {
        var plateList = ObjectContext.Plates
            .Where(p => p.RestaurantID == restaurant.ID)
            .Where(p => p.Name.Contains(term));
        foreach (var plate in plateList)
            restaurant.Plates.Add(plate);
    }
 
    //Find all restaurants that match
    var restaurantsList = this.ObjectContext.Restaurants
        .Where(r => r.Name.Contains(term) &&
                    !restaurantPlatesList.Contains(r));
 
    return restaurantPlatesList.Concat(restaurantsList);
 
}         
 
 

In line 1, you see that we are defining a new query that returns Restaurants… this one has a different name, and takes a search term as an argument.

In line 4-6, we are getting all the restaurants that that have any plates that match the search term.

In line 7-14, we are looping through all those restaurants and manually adding the plates that match to the collection we will return. Effectively, we are manually creating the instance in just the shape we need it for the client.

In line 17-18, we are getting the Restaurants that match and that are not already included.

and finally, in line 21, we return the concatenation of the two queries.

Notice that this query is designed to return Restaurants AND the Plates that are related. By default, related entities are not included (in order to save bandwidth).. so we need to go into the metadata file and explicitly include them.

 internal sealed class RestaurantMetadata
{
    [Include]
    public EntityCollection<Plate> Plates;

Now, in the Silverlight client. First we need to wire up the Search button on MainPage.xaml.. There we just need to follow the same pattern we saw in the earlier post:

 private void button1_Click(object sender, RoutedEventArgs e)
{
    ContentFrame.Navigate(new Uri("/Search?term=" + searchBox.Text,
                            UriKind.Relative));
}
 
 

Then the search page, again we build it the same way as we saw in the earlier post, by simply drag and dropping from the data sources window. Notice that we now have two different query methods for Restaurants. So we simply select the right one and then drag and drop on the form as we saw in the earlier post:

After we get the UI laid out correctly you end up with a pager and all the columns set right.

Then wire up the parameter to the SearchRestaurants query method to the query string…

 protected override void OnNavigatedTo(NavigationEventArgs e)
{
    this.restaurantDomainDataSource.QueryParameters.Add(
    new System.Windows.Data.Parameter()
    {
        ParameterName = "term",
        Value = NavigationContext.QueryString["term"]
    });
}
 

Now i’d like to display the Plates for each Restaurant that is returned. To do that, i’ll make use of the RowDetails feature of DataGrid.

 <data:DataGrid.RowDetailsTemplate>
        <DataTemplate>
            <ListBox ItemsSource="{Binding Plates}">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <StackPanel Orientation="Horizontal">
                            <Image  Source="{Binding Path=IconPath, Converter={StaticResource ImagePathConverter1}}"
                                    Margin="40,0,10,0"></Image>
                            <StackPanel>
                                <TextBlock  Text="{Binding Path=Name}" Width="400"
                                            TextWrapping="Wrap"
                                            FontWeight="Bold"></TextBlock>
                                <TextBlock Text="{Binding Path=Description}" Width="400"
                                           TextWrapping="Wrap"></TextBlock>
                                <HyperlinkButton Click="HyperlinkButton_Click"
                                                 Content="Details..."
                                                 NavigateUri="{Binding ID}" />
                            </StackPanel>
                        </StackPanel>
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>
 
        </DataTemplate>
    </data:DataGrid.RowDetailsTemplate>
 

Run it and we get this sort of view…

Notice the URL includes the search term, so I can send this around in email to share my search results bookmark it for future reference.

Now, you might want to drill into the details on what of these plates… so let’s handle that “Details..” hyperlink. In the code behind for the search page, we handle navigating to the Plates page with a the right query string paramaters.

 private void HyperlinkButton_Click(object sender, RoutedEventArgs e)
{
    var button = sender as HyperlinkButton;
    var plate = button.DataContext as Plate;
 
    NavigationService.Navigate(
        new Uri("/Plates?restaurantId=" + plate.RestaurantID + "&" +
                "plateId=" + plate.ID,
        UriKind.Relative));
}
 
 

Now we need to make a slight tweak to the Plates page because it does no know about the plateId query string parameter.

 protected override void OnNavigatedTo(NavigationEventArgs e)
{
    //Handle RestaurantID
    plateDomainDataSource.QueryParameters.Add(
        new System.Windows.Data.Parameter()
        {
            ParameterName = "resId",
            Value = NavigationContext.QueryString["restaurantId"]
        });
 
 
    //Handle PlateID
    var qs = NavigationContext.QueryString;
    if (qs.ContainsKey("plateId"))
    {
        this.plateDomainDataSource.FilterDescriptors = 
            new FilterDescriptorCollection();
        this.plateDomainDataSource.FilterDescriptors.Add(
              new FilterDescriptor("ID",
                  FilterOperator.IsEqualTo, qs["plateId"]));
    }
}
 
 

The first few lines to handle the RestaurantID were already there, so we just needed to add the code to handle the PlateID.. Notice we don’t need to change the query method on the server for this, we just add a new where clause that will get sent to the server and executed there.

The result:

Again, notice the URL, something we can bookmark or send around in email, etc.

I hope you got something valuable from this walkthrough… You can download the completed solution as well and be sure to check out the full talk.

Have fun!

RIA Services: A DomainService IS A WCF Service – Add Service Reference

BradA — Mon, 23 Nov 2009 07:57:37 GMT

I made the fairly bold statement at my PDC09 talk that a DomainService IS A WCF Service. That is, everything you know about a WCF service should be true of a DomainService. I didn’t have time to get into this in my talk, so I thought I’d hit the highlights here. And in the process show how to consume a DomainService from a WinForms. You can also see more examples at: http://code.msdn.microsoft.com/RiaServices

You need:

Visual Studio 2010 Beta 2 (this actually works exactly the same in VS2008 and the corresponding RIA Services drop)
Silverlight 4 Beta

You can download the completed solution as well. and be sure to check out the full talk.

1. Getting to the Service

The first thing we need to do is get at the data underlying service. In the mainstream Silverlight case this is all handled for you by the implicit link between the Silverlight client and the ASP.NET server. However, in the vanilla WCF case, you get the full control. The URL to the service is of the following format:

http://[hostname]/[namespacename]-[classname].svc

so in my case that is:

http://localhost:30335/Services/MyApp-Web-DishViewDomainService.svc

Hitting that URL in the browser gives you the very familiar WCF proxy help screen:

And tacking on the ?wsdl gives you the WSDL for this service

http://localhost:30335/Services/MyApp-Web-DishViewDomainService.svc?wsdl

The rest is easy for anyone halfway familiar with WCF… Create a new WinForms project and select Add Service Reference. Enter the URL (note discover doesn’t work for this sort of service yet)…

The you have a service!

2. Querying for the Data

Now, we have a service, let’s look at actually getting data out of it. In this case I already have a WinForms DataGridView on my form. So getting data into it should be no problem.

 private void Form1_Load(object sender, EventArgs e)
{
    var context = new DishViewDomainServiceClient("BasicHttpBinding_DishViewDomainService");
    var plates = context.GetPlates(4);
    this.dataGridView1.DataSource = plates.RootResults;
    foreach (DataGridViewRow row in dataGridView1.Rows)
    {
        PlatesListOriginals.Add(ToPlate(row));
    }
    dataGridView1.CellEndEdit += dataGridView1_CellEndEdit;
    dataGridView1.SelectionChanged += dataGridView1_SelectionChanged;
}
 
 

In line 3, we create a new instance of the web service client and point it at the right binding. The service exposes a couple of different bindings as you can see in the app.config file for the WinForms app:

 <endpoint address="http://localhost:30335/Services/MyApp-Web-DishViewDomainService.svc/soap"
    binding="basicHttpBinding" bindingConfiguration="BasicHttpBinding_DishViewDomainService"
    contract="ServiceReference1.DishViewDomainService" name="BasicHttpBinding_DishViewDomainService" />
<endpoint address="http://localhost:30335/Services/MyApp-Web-DishViewDomainService.svc/binary"
    binding="customBinding" bindingConfiguration="BinaryHttpBinding_DishViewDomainService"
    contract="ServiceReference1.DishViewDomainService" name="BinaryHttpBinding_DishViewDomainService" />
 
 

In line 4, we call the service to get our list of Plates… in this case we are doing things synchronously.. you could of course do it async if you’d like.

In line 5, we bind the DataGridView to the results of this call.

In lines 6-9, we are saving off the “original” values.. for each item we got.. this will help us when we do updates.

In line 10, we handle the cell edit event, we will come back to look at that later.

in line 11, we sign up for the selection changed event so we can initialize the picture…

 void dataGridView1_SelectionChanged(object sender, EventArgs e)
{
     Plate currentPlate = ToPlate(dataGridView1.CurrentRow);
     this.pictureBox1.ImageLocation = "http://hanselman.com/abrams/Images/Plates/" + currentPlate.ImagePath;
}
 
 

Be patient with this one… sometimes it takes a while load a picture. it is using hanselman’s server which gets slammed sometimes ;-)

Now we have our data, we can scroll through it and view the pretty pictures.

3. Updating the Data

But how do we update the data… well, let’s take a look at CellEditEnd event handler…

 void dataGridView1_CellEndEdit(object sender, DataGridViewCellEventArgs e)
{
    var context = new DishViewDomainServiceClient("BasicHttpBinding_DishViewDomainService");
    Plate currentPlate = ToPlate(dataGridView1.Rows[e.RowIndex]);
    ChangeSetEntry[] changeSet = new[] {
        new ChangeSetEntry{
         OriginalEntity = PlatesListOriginals[e.RowIndex],   
         Entity = currentPlate,
         Operation = DomainOperation.Update
        }
    };
    context.SubmitChanges(changeSet);
}
 
 

In line 3, we are creating a new context. we could be sharing with the load method, but I thought this would be cleaner to follow.

In line 4, we save off the currently selected plate.

In lines 5-10 we are building up a changeset to send to the server.

Notice we need to give it the original values we saved off in the load method. Getting the original values right is the likely the hardest part here. Keep in mind that assignment in C# (and VB) is by default by reference. So you can’t just store off a reference, you must actually make a copy of the original values.

Then in line 12, we submit the changes.

Make a change, tab off it.. This will call the server and post your update. Re run the app to see that it took.

Notice here we are sending one item in the change set. You could of course build up a change set on the client with many entries and then send them as a batch.

I hope that helps to make it clear how a DomainService IS A WCF Service… You can download the completed solution as well. and be sure to check out the full talk.

PDC09 Talk: Building Amazing Business Applications with Silverlight 4, RIA Services and Visual Studio 2010

BradA — Thu, 19 Nov 2009 21:30:00 GMT

I had a great time at my talk today at PDC2009. I was able to spend much of the time in a demo… Here is a summary of that demo so you can walk through it on your own machine:

What you need to get started:

Visual Studio 2010 Beta2
Silverlight 4 Beta (now includes RIA Services)
Completed Solution (starting step and demo files)
Check out the slides

Starting Off

I am starting off with the new Business Application Template that gets installed with RIA Services.

This new template includes:

Pattern for page navigation
Log\Logout and new user registration support
Localizable
User settings
Shared Code

For this demo, I am going to used a customized version of the template..

Exposing the Data

So here is the EF model I created. Basically we have a set of restaurants, each of which has a set of plates they serve. A very simple model designed many to show off the concepts.

Then we need to place to write our business logic that controls how the Silverlight client can interact with this data. To do this create a new DomainService.

Then select the tables you want to expose:

Now, let’s look at our code for the DomainService…

 using System.Linq;
using System.Web.Ria;
using System.Web.DomainServices.Providers;
 
namespace MyApp.Web
{
    [EnableClientAccess]
    public class DishViewDomainService : 
            LinqToEntitiesDomainService<DishViewEntities>
    {
        public IQueryable<Restaurant> GetRestaurants()
        {
            return this.ObjectContext.Restaurants
                .Where (r=>r.City != "Raleigh")
                .OrderBy(r=>r.ID);
        }
    }
}
 

In line 7 – we are enabling this service to be accessed from clients.. without this, the DomainService is only accessible from on the machine (for example for an ASP.NET hosted on the same machine).

In line 8: we are defining the DomainService – you should think of a DomainService as just a special kind of WCF Service.. one that is higher level and has all the right defaults set so that there is zero configuration needed. Of course the good news is that if you *need* to you can get access to the full richness of WCF and configure the services however you’d like.

In line 9: you see we are using the LinqToEntitiesDomainService. RIA Services supports any DAL including LinqToSql or NHibernate. Or what I think is very common is just POCO.. that is deriving from DomainService directly. See examples of these here…

In line 11: We are defining a Query method.. this is based on LINQ support added in VS2008. Here we define the business logic involved in return data to the client. When the framework calls this method, it will compose a LINQ query including paging, sorting, filtering from the client then execute it directly against the EF model which translate it into optimized TSQL code. So no big chunks of unused data are brought to the mid-tier or the client.

Consuming the data on the client

Now let’s switch over the client project and look at how we consume this.

in Views\Home.xaml we have a very simple page with just a DataGrid defined.

 <Grid x:Name="LayoutRoot">
    <data:DataGrid AutoGenerateColumns="True"
                   Name="dataGrid1"
                   Height="456"
                   Width="618" />
</Grid>
 
 

now let’s flip over to codebhind..

Notice we have a MyApp.Web namespace available on the client. Notice that is the same namespace we defined our DomainService in..

 var context = new DishViewDomainContext();
dataGrid1.ItemsSource = context.Restaurants;
 
context.Load(context.GetRestaurantsQuery());

Now we run it..

RIA Services support in Visual Studio 2010

Let’s delete that code we just wrote and flip over to the design surface and delete that datagrid.

Drop down the DataSources window (you may need to look under the Data menu for “Show Data Sources”

Now, drag and drop Restaurant onto the form and we get some UI

And for you Xaml heads that want to know what really happens… Two things. First if the DomainDataSource is not already created, one is created for you.

 <riaControls:DomainDataSource AutoLoad="True"
                              Height="0"
                              LoadedData="restaurantDomainDataSource_LoadedData"
                              Name="restaurantDomainDataSource"
                              QueryName="GetRestaurantsQuery"
                              Width="0"
                              Margin="320,240,320,144">
    <riaControls:DomainDataSource.DomainContext>
        <my:DishViewDomainContext />
    </riaControls:DomainDataSource.DomainContext>
</riaControls:DomainDataSource>
 
 

If you notice the LoadedData event is wired up… This is to give a nice user experience in the case of an error. You should certainly customize what is defaulted for you… but it is a good place to start.

 private void restaurantDomainDataSource_LoadedData(object sender, 
    LoadedDataEventArgs e)
{
    if (e.HasError)
    {
        MessageBox.Show(e.Error.ToString(), "Load Error",
            MessageBoxButton.OK);
        e.MarkErrorAsHandled();
    }
}
 

Finally, the DataGrid is created with a set of columns.

 <data:DataGrid AutoGenerateColumns="False"
               ItemsSource="{Binding ElementName=restaurantDomainDataSource, Path=Data}"
               Name="restaurantDataGrid"
               RowDetailsVisibilityMode="VisibleWhenSelected">
    <data:DataGrid.Columns>
        <data:DataGridTemplateColumn x:Name="imagePathColumn"
                                     Header="Image Path"
                                     Width="SizeToHeader">
            <data:DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Image Source="{Binding Path=ImagePath}" />
                </DataTemplate>
            </data:DataGridTemplateColumn.CellTemplate>
        </data:DataGridTemplateColumn>
        <data:DataGridTextColumn x:Name="nameColumn"
                                 Binding="{Binding Path=Name}"
                                 Header="Name"
                                 Width="SizeToHeader" />
        <data:DataGridTextColumn x:Name="addressColumn"
                                 Binding="{Binding Path=Address}"
                                 Header="Address"
                                 Width="SizeToHeader" />
 
 

Then setup a grid cell by click 4/5ths of the way down on the left grid adorner. Then select the grid, right click, select reset layout all.

.. add poof! VS automatically lays out the DataGrid to fill the cell just right.

In this designer you can control the order of columns and the layout, etc. I moved the image and name fields to the top.

Now, let’s add a DataPager such that we only download a manageable number of records at a time. From the toolbox, simply drag the datapager out.

We use our same trick to have VS auto layout the control Right click on it and select Reset Layout\All.

That is cool, but there is a big gap between the DataGrid and the DataPager.. I really want them to be right. This is easy to fix. Right click on the grid adorner and select “Auto”..

Perfect!

Now, we just need to wire this up to the same DataSource our DataGrid is using “connect-the-dots” databinding. Simply drag the Restaurant from the DataSources window on top of the DataGrid.

For you Xaml heads, you’ll be interested in the Xaml this creates..

 <data:DataPager Grid.Row="1"
                Name="dataPager1"
                Source="{Binding ElementName=restaurantDomainDataSource, Path=Data}" />
 
 

Notice, we don’t need to create a new DomainDataSource here… we will use the one that is already on the page.

Now, we are doing an async call.. so let’s drag a BusyIndicator from the new Silverlight 4 Toolkit.

We need to write up the IsBusy to the restaurantDomainDataSource.DomainContext.IsLoading… Luckily there is some nice databinding helper in VS2010. Select properties, then IsBusy, then DataBinding.

Again, for you Xaml heads, the Xaml that gets generated is pretty much what you’d expect.

 <controlsToolkit:BusyIndicator Height="78"
                               HorizontalAlignment="Left"
                               Margin="226,201,0,0"
                               Name="busyIndicator1"
                               VerticalAlignment="Top"
                               Width="177"
                               IsBusy="{Binding ElementName=restaurantDomainDataSource, Path=DomainContext.IsLoading}" />
 
 

Loading…

and once it is loaded…

 public class ImagePathConverter : IValueConverter
{
 
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        string path = value.ToString();
        path = path.Replace(":", "");
        path = path.Replace("/", "");
        path = path.Replace("\\", "");
        if (path.Length > 100)
            path = path.Substring(0, 100)
        return "http://localhost/Images/" + path
    }
 
 

Now, let’s look at how we wire this converter to the UI. First, let’s use the Document Outline to drill through the visual tree to find the Image control.

Then we select the properties on the image and wire up this converter. If you have done this in Xaml directly before, you know it is hard to get right. VS2010 makes this very easy!

Oh, and for you Xaml heads… here is what VS created..

 <navigation:Page.Resources>
    <my1:ImagePathConverter x:Key="ImagePathConverter1" />
</navigation:Page.Resources>
 
 

and

 <data:DataGridTemplateColumn.CellTemplate>
    <DataTemplate>
        <Image Source="{Binding Path=ImagePath, Converter={StaticResource ImagePathConverter1}}" />
    </DataTemplate>
</data:DataGridTemplateColumn.CellTemplate>
 
 

Silverlight Navigation

First we add a bit of Xaml to add the link to the datagrid..

 <data:DataGrid.Columns>
    <data:DataGridTemplateColumn Header="">
        <data:DataGridTemplateColumn.CellTemplate>
            <DataTemplate>
                <Button Content="+"
                        Style="{StaticResource DetailsButtonStyle}"
                        Click="Button_Click"></Button>
            </DataTemplate>
        </data:DataGridTemplateColumn.CellTemplate>
    </data:DataGridTemplateColumn>
 
 

And to implement the button click handler…

 private void Button_Click(object sender, System.Windows.RoutedEventArgs e)
 {
 
     var res = this.restaurantDomainDataSource.DataView.CurrentItem 
         as Restaurant;
 
     NavigationService.Navigate(new Uri("/Plates?restaurantId="
         + res.ID, UriKind.Relative));
 
 }

Here we are getting the currently selected Restaurant, then we cons up a new URL to the page “Plates”. We pass a query string parameter of restaurantId…

Now, let’s build out the Plates page that will the list of Plates for this restaurant. First let’s great a a Plates page. Let’s add a new Plates under the Views directory.

Now we need to define a query to return the Plates. Notice that only the data you select is exposed. So we get to go back to the server, to our DishViewDomainService and add a new query method.

 public IQueryable<Plate> GetPlates()
{
    return this.ObjectContext.Plates
        .OrderBy(p => p.Name);
}
 
 

Now we go back to the client, and see your DataSources window now offers a new datasource: Plates.

Now, just as we saw above, I will drag and drop that data source onto the form and i get a nice datagrid alreayd wired up to a DomainDataSource.

Then, with a little formatting exactly as we saw above, we end up with…

And when we run it… First, you see the link we added to the list of Restaurants..

Clicking on anyone of them navigates us to our Plates page we just built.

Customized Data Access

 public IQueryable<Plate> GetPlates(int resId)
{
    return this.ObjectContext.Plates
        .Where (p=>p.RestaurantID == resId)
        .OrderBy(p => p.Name);
}
 

Now, back on the client, we just need to pass the query string param…

 protected override void OnNavigatedTo(NavigationEventArgs e)
{
    plateDomainDataSource.QueryParameters.Add(
    new System.Windows.Data.Parameter()
    {
        ParameterName = "resId",
        Value = NavigationContext.QueryString["restaurantId"]
    });
}
 
 

Now, we run it and we get the just the plates for the restaurant we selected.

what’s more is we now have a deep link such that it works when I email, IM or tweet this link to my buddy who happens to run a different browser ;-)

Ok… now for a details view… Let’s do a bit more layout in the Plates.xaml. First, let’s split the form in half vertically to give us some cells to work in.

In the bottom left we will put the details view to allow us to edit this plate data. Let’s go back to the DataSources window and change the UI type to Details.

Dragging that Details onto the form… we get some great UI generation that we can go in and customize.

In particular, let’s format that Price textbox as a “currency”… using the new String Formatting support in Silverlight 4.

And again, for you Xaml heads… this created:

 Text="{Binding Path=Price, Mode=TwoWay, ValidatesOnExceptions=true, NotifyOnValidationError=true, StringFormat=\{0:c\}}"
 

Now, let’s add an image to the other side. Simply drop an Image control on the form and select Reset Layout\All

Now we can easily change the image to be “Uniform”

Now we need to write up the binding here so that as selection changes, this image is update. Luckily, that is very easy to do. Simply drag and drop from the Data Sources window…

Then we need to wire up our converter just as we saw before..

Run it…

That looks great!

But when we try edit something, we get this error..

Editing Data

Ahh, that is a good point, we need to go back and explicitly define a Update method to our DomainService on the server.

 public void UpdatePlate(Plate currentPlate)
{
    currentPlate.NumberUpdates++;
 
    var orginal = this.ChangeSet.GetOriginal(currentPlate);
 
    if (orginal.Price != currentPlate.Price)
    {
        currentPlate.Price += 1; // add 1 dollar fee for changing price
    }
 
    this.ObjectContext
        .AttachAsModified(currentPlate, orginal);
}
 
 

In line 3, notice we take the NumberUpdates and increment by one. it is nice that we send the entry entity back and forth, so we can do entity level operations very easily.

Next in line 5, we pull out the original value.. .this is the plate instance as the client saw it before it was updated.

In line 7-10, we first check to see if the price has changed, if it has, we add a fee of one dollar for a price change.

Finally in line 12-13, we submit this change to the database.

Now we just need to drop a button on the form.

Then write some codebehind..

 private void button1_Click(object sender, RoutedEventArgs e)
{
    this.plateDomainDataSource.SubmitChanges();
}
 
 

What this is going to do is find all the entities that are dirty (that have changes) and package them up and send them to the server.

Now notice if you make a change price to the data and hit submit the NumberUpdates goes up by one and the the price has the one dollar fee added.

Then submit.. NumberUpdates is now 63 and the price is $73.84..

Great.. now let’s look at data validation.

We get some validation for free. for example Calorie Count is a int, if we put a string in, we get a stock error message.

 [Required(ErrorMessage = "Please provide a name")]
public string Name;
 
public Nullable<int> NumberUpdates;
 
[Range(0, 999)]
public Nullable<decimal> Price;
 
[RegularExpression(@"^http\://[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(/\S*)?$",
    ErrorMessage = "Please use standard Url format")]
public string Uri;
 
 

The data validation attributes are a core part of .NET with ASP.NET Dynamic Data and ASP.NET MVC using the exact same model.

Notice the name here PlateValidationRules.shared.cs…. the “.shared” part is important… it is what tells us that this code is meant to be on the client and the server.

In this case, i am saying a valid description is one that has 5 more more words

 public class PlateValidationRules
{
    public static ValidationResult IsDescriptionValid(string description)
    {
        if (description != null && description.Split().Length < 5)
        {
            var vr = new ValidationResult("Valid descriptions must have 5 or more words.");
            return vr;
        }
 
        return ValidationResult.Success;
    }
 
 

Then to wire this up to the description property…

 [CustomValidation(typeof(MyApp.Web.PlateValidationRules),
       "IsDescriptionValid")]
public string Description;
 
 

Then running the app, we see all our validations…

Personalization and Authentication

 [EnableClientAccess]
[RequiresAuthentication] 
public class DishViewDomainService : 
        LinqToEntitiesDomainService<DishViewEntities>
{
 
 
 

Then when you run the application..

Here we are creating a new user…

And now we get our data…

Now, that we have a user concept.. why don’t we add one more setting to let the user customize this page. So we edit the web.config file to add a BackgroundColor.

 <?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.web>
 
    <profile>
      <properties>
        <add name="FriendlyName" />
        <add name="BackgroundColor"/>
      </properties>
    </profile>
 
 

And we go into the User.cs class on the server and add our BackgroundColor.

 public partial class User : UserBase
{
    public string FriendlyName { get; set; }
    public string BackgroundColor { get; set; }
}
 
 

Drag and drop that onto the form..

Then change the binding to be TwoWay using the databinding picker.

Then I think we need a nice header here with the User name in it. To so that, let’s add a TextBlock, set the fontsize to be big. Then do connect the dots databinding to write up to the user name.

Then let’s use the string format databinding to customize this a bit..

Next we put a Submit button.

 private void button1_Click(object sender, System.Windows.RoutedEventArgs e)
{
    var context = WebContext.Current.Authentication;
 
    this.userDomainDataSource.SubmitChanges();
    userDomainDataSource.SubmittedChanges += (s, ev) =>
    {
        if (!context.IsBusy) context.LoadUser();
    };
}
 
 

Now when we run it… we can modify the user settings.

The really cool part is that if the user goes to another machine and logs in, they get the exact same experience.

Summary

Welcome to WCF RIA Services Beta!

BradA — Wed, 18 Nov 2009 16:57:43 GMT

Today at PDC09, Scott Guthrie Announced the beta of WCF RIA Services. As you may know RIA Services is a set of end-to-end experiences that makes it as easy to build Silverlight based n-tier applications as it is to build traditional 2 tier apps. I am very excited about this release as it represents a lot of great feedback we have heard from many of you.

A few goodies in this release based on your feedback

You told us you wanted to get up and running with the UI quicker, so we enabled the “DataSources” window that allows you to drag and drop “tables” exposed by your Domain Service onto the form and get meaningful UI to start with. No more guessing about the Xaml syntax for databinding, or incantation for layout, etc.

You told us error handling was not intuitive\consistent with the rest of the framework, so we we simplified error handing both on the server and client. This will help errors get noticed quicker at development time so they don’t sneak into production
You told us you wanted Inheritance support from the Data Model to just flow through the Domain Service to the client, so we gave it to you, works exactly as you’d expect.
You told us you didn’t always want to expose DAL types to the client, but rather a custom “presentation model” where you can customize the shape of the entities, so we gave it to you.. and in a complete way where we handle all the update and error cases.
You told us you wanted the fastest possible communication channel between the client and the server, so we gave an optimized binary channel by default!
You told us it was a pain to install so we integrated the RIA Services installer into the Silverlight 4 installer making it very easy to get started. We also created a “server only” installer to use on your production boxes.
You told us real world data models use a lot of Compositional hierarchy (Order->OrderDetails) so we have improved the handling of this scenario by making it more built in.
You told us you wanted GAC *and* bin deployment. So we gave it to you. By default RIA Services look for our server assemblies in the GAC as this is the most secure and efficient model, but just like ASP.NET MVC, you can simply select “copy local” in your VS project and those assemblies work fine bin deployed.
You told us you really liked the easy on ramp with the Business Application Template, but that you wanted it to be more complete. So we added globalization support, user state example, persisted sign in, etc.
You told us you wanted to go live today (and many of you already have) so we are providing .NET Framework 3.5\Visual Studio 2008\Silverlight 3 based bits that are ready for you to go live on today! We hope that this release will be a bridge to you that will make it easier for you to (eventually, when you are ready) move to our finally RTM bits which will be on .NET Framework 4, Visual Studio 2010 and Silverlight 4.
You gave us a LOT of other feedback as well, some of which will come in V1, and some will have to wait until the next releases, but please keep it coming.

WCF: What’s in a Name?

Many of you will notice the slight change in the branding around RIA Services. RIA Services is now part of the WCF family (as is ADO.NET Data Services, which is now WCF Data Services). This branding change is a direct result of some significant work we are releasing in this beta and it hopefully makes it very clear that we have one technology base for doing services on the .NET platform and that is WCF.

Our driving principle with using WCF has been “All the power and none of the complexity”. That is we wanted to enable all the power that WCF brings (for example, the binary end-point, data contract serialization, all the extensibility points, fully management support with the AppFabric we announced yesterday). But none of the complexity. Just look at the web.config file… there is no tedious config to get right.. there is no fragile contract interface and implementation class to keep in sync, none of the deployment headache around configuration. This is still the RIA Services model where you can expect a deep simplicity across development, deployment and maintenance. We accomplish this by creating a custom service host at runtime based on how you define your DomainService.

I am also very excited to get OData support into RIA Services. OData is the protocol from “Astoria” that is already widely used in products like Sharepoint and PowerPivot. Look for more details on that in future.

Check out Henrik Frystyk Nielsen’s talk Developing REST Applications with the .NET Framework which will cover how WCF Data Services and WCF RIA Services work together.

Call to Action

1. Please install Visual Studio 2010 and Silverlight 4 (this includes RIA Services)

2. Build something cool and tell us about it!

3. Send in your feedback.. we want to hear what rocked, and what needs more polish

http://silverlight.net/riaservices/ is Live!

BradA — Sun, 08 Nov 2009 02:03:03 GMT

We have been working for a while to get a community site together where we can aggregate all the great buzz, resources and discussions about .NET RIA Services. We hope you enjoy the content we already have up there and help us get more good stuff up there.

http://silverlight.net/riaservices/

We Need Your Feedback on the Documentation

BradA — Fri, 30 Oct 2009 16:49:25 GMT

The doc teams are looking for your feedback on the .NET Framework and Visual Studio docs. Help us improve the developer documentation by taking the Visual Studio and .NET Framework Content Survey. This survey will give us a better understanding of the type of applications you are developing as well as how you use Help and how we can improve it. The survey takes only 10 minutes, and we really appreciate your feedback! Feel free to forward the survey link.

Lightweight Linq Parser

BradA — Wed, 28 Oct 2009 19:28:30 GMT

Jason Allor, dev manager for my team, recently posted about a cool lightweight LINQ parser. The idea was to make it much easier to create a LINQ provider over any arbitrary data source (a web service, custom business objects, etc). This makes it much easier to get all the sorting, paging, filtering benefits of RIA Services for any arbitrary data store.

Check it out, and be sure to subscribe to Jason’s blog as I expect he will have more goodies coming in the future!

LinqLite

Index for Business Apps Example for Silverlight 3 RTM and .NET RIA Services July Update

BradA — Tue, 27 Oct 2009 15:46:21 GMT

Thanks to all of you who asked… I had to take a sick day today, so this was nice mindless work to get done. Hope you enjoy it!

Part 1: Navigation Basics

Part 2: Rich Data Query

Part 3: Authentication

Part 4: SEO, Export to Excel and Out of Browser

Part 5: Astoria, Add Service Reference and WinForms

Part 6: Data Transfer Objects (DTOs)

Part 7: ADO.NET Data Services Based Data Store

Part 8: WCF Based Data Source

Part 9: POCO and Authentication Provider

Part 10: LinqToSql

Part 11: The Client-Only World

Part 12: DataSet

Part 13: The New Class Library Project

Part 14: Visual Basic (VB) and WPF Support

Part 15: ASP.NET MVC

Part 16: Exposing a WCF Service

Part 17: Evolving an Application

Part 18: Custom Linq Provider

Part 19: ASP.NET Dynamic Data

Part 20: NHibernate

Part 21: Hierarchical Data

Part 22: Separate Solution Files

Part 23: Azure

Part 24: Stored Procedures

Part 25: ViewModel

Part 26: Authentication and Personalization

Comments about Adding…

Summary

Mozilla and Microsoft work together on WPF\ClickOnce plugins

BradA — Wed, 21 Oct 2009 19:01:47 GMT

Recently some friends mentioned that they saw Firefox had block-listed some Microsoft WPF\ClickOnce add-ons. As Mike Shaver (VP Engineering for the Mozilla) noted in his blog post, this action is the result of Mozilla and Microsoft working together to protect customers in relation to Security Update MS09-054.

I think it is very important for Microsoft and Mozilla to collaborate so actively to help protect customers… in this case we all agreed it made sense to add the Microsoft add-in to the block-list. We also heard clearly that many customers, especially enterprise customers are relying on this add-on for their daily work. As such Mozilla and Microsoft are working together to give these customers the best possible experience. Like Mike mentioned, as we learned more about MS09-054, we felt mutually good about re-enabling the clickonce addon and as this security fix hits market saturation, we expect to feel comfortable with re-enabling the WPF add-on as well.

We've heard loud and clear from customers how we need to work better with Mozilla around how our plug-ins and add-ons interact with Firefox. And I can promise you that our group will continue to collaborate with Mozilla to more proactively notify them of the effect of updates in the future to help ensure customers have interoperable solutions for their business needs.

I’d like to thank Mike and his team at Mozilla for their great work on this issue and look forward to working with them in the future.

RIA Services Blog Posts – Now in French!

BradA — Fri, 16 Oct 2009 05:21:44 GMT

Thanks to Yannick Aristidi we are getting many of the RIA Services posts from my series translated into French!

Thanks Yannick, i hope there are many more to come!

Enjoy!

PDC 2009 – I can’t wait!

BradA — Wed, 14 Oct 2009 17:01:08 GMT

Things are really starting to heat up around here as we get ready for the PDC. Just this week I have talked to folks on Silverlight, Visual Studio, Azure, ASP.NET, .NET RIA Services, MEF that all have very cool new stuff to talk about at the PDC.

We just recently announced the Scott Guthrie will be giving one of the keynotes, so you can be sure that will be fun.. You can bet Scott will be talking about the latest from ASP.NET, Silverlight, the .NET Framework and Visual Studio!

I will also be there to talk about building business application in Silverlight… no rotating images or dancing videos in this talk, it will be all about saving you and your end user’s time by taking advantage of the latest in Silverlight, .NET RIA Services and Visual Studio!

Hope to see you there, but there will also be lots of good content on line if you can’t make it..

Find out more information here: http://microsoftpdc.com/

When I have talked to developers in the past about coming to PDC, one of the things has been convincing their boss that it is worth the time and money.. I’d love to hear any success stories you have had. How have you sold the PDC to your boss? what works?