Beth's Chinese blog
Check it out, I’ve got another podcast with Richard and Carl this time talking about the new features in LightSwitch in Visual Studio 11. I always have a ton of fun talking with these guys and you can tell I’m super excited about the next version of LightSwitch.
Show #769: Beth Massi Builds Apps with LightSwitch in Studio 11
Carl and Richard talk to Beth Massi about the latest incarnation of LightSwitch. In 2011 LightSwitch shipped as a separate install, but the upcoming version of LightSwitch is part of every SKU of Studio 11. Beth talks about how LightSwitch has evolved to be an awesome consumer and creator of data, making it simple to create oData interfaces over anything. The conversation also digs into the role of Silverlight, the evolution of the client and how LightSwitch makes apps in the cloud much simpler.
Enjoy!
On Friday last week I delivered a webcast on the new LightSwitch features in Visual Studio 11 beta. I think it went pretty well considering it was the first time I had done the session end-to-end :-). You can now view the webcast recording here:
Download: What's New with LightSwitch in Visual Studio 11WMV Download | WMA | MP4
In the session we built an application called “Media Mate” that connects to the Netflix OData source to keep track of favorite movies and music. I showed off new features around all our OData work like how to consume external OData services. I also demonstrated how LightSwitch creates its own OData services adhering to your business rules and security settings so that other clients on different platforms can access your middle-tier easily and securely. I showed off some of the new UI enhancements and business types as well as some of the new deployment enhancements. I attached the presentation slides to the bottom of this post.
One demo hiccup happened where I messed up the search ability over the Netflix data. Doh! What I ended up doing is unchecking the IsSearchable property on the Title entity in the data designer which subsequently disabled the searching on the screen. So it was user error, not a beta bug ;-). At any rate, I think folks got the point. By the way, there are a lot of things you can do to improve search query performance in LightSwitch and I’ll follow up with a post about that soon.
I also demonstrated the updated Contoso Construction sample that you can download here:
Contoso Construction - LightSwitch Advanced Sample (Visual Studio 11 Beta)
For more information on the new features I demonstrated please see:
Also don’t forget to visit the LightSwitch Developer Center, your one-stop-shop for learning all about LightSwitch.
One of the design goals for LightSwitch in Visual Studio 11 was to modernize the look and feel of the UI. Back in March the team released the beta of the LightSwitch Cosmopolitan Shell and Theme. This theme and shell provides a bunch of improvements over the default one like displaying a logo at the top of the application, streamlined top-bar navigation menu, and a “Metro-style” command bar now located at the bottom of screens. This shell will become part of the product and the default shell and theme for new projects you build with LightSwitch in Visual Studio 11 at final release.
So I attempted to apply the Cosmo shell to my Contoso Construction application a while back and I got a couple remarks about how my icons were pretty much sticking out like a sore thumb. I used traditional colorful icons in the application and while that looks great with the standard shell, it doesn’t fit well with the Metro-style icons in the Cosmopolitan shell. Unfortunately I didn’t have time to redraw the icons -- and let’s face it, I’m not a designer.
Luckily there’s a FREE tool out there that you can use to quickly create Metro-style icons! Last night I was reviewing a LightSwitch e-book from Jan (to be released soon I hear!) and he mentioned this free tool so I had to go check it out, Syncfusion Metro Studio. And yes it’s free! Thank you Syncfusion for supporting the community (and particularly the developers who can’t draw!)
This tool comes with a bunch of icon templates you can use to get started designing your own Metro-style icons and it’s super easy to use.
Pick a template and then you can change the sizing, shape, foreground, and background color. You can also view & copy the XAML or save it as a PNG.
For LightSwitch applications that use the Cosmo shell, it’s best to go with a Transparent background so that the light grey of the command bar comes through. Although Metro Studio doesn’t let you choose a transparent background in the color picker, you can simply type it in the textbox (like I show above).
It took me about 20 minutes to update all the icons in the Contoso Contruction application and here’s what I came up with. Not bad for not being a designer :-). You can download the updated sample here:
Syncfusion Metro Studio is a huge time-saver and all the icons you create are royalty-free even for commercial applications. Have fun “Metro-styling” your apps!
I’ll be speaking next week at the East Bay.NET User Group in Berkeley as well as delivering a MSDN webcast on What’s New with LightSwitch in Visual Studio 11. I hope you can either make it in person or join in online to see and discuss the exciting new features LightSwitch will bring you. I always have a blast delivering these so I hope you can join!
What's New with LightSwitch in Visual Studio 11 Microsoft Visual Studio LightSwitch is the simplest way to build business applications and data services for the desktop and the cloud. LightSwitch contains several new features and enhanced capabilities in Visual Studio 11. In this demonstration-heavy webcast, we walk through the major new features, such as creating and consuming OData services, new controls and formatting, new features with the security system and deployment, and much more.
East Bay.NET User Group: What's New with LightSwitch in Visual Studio 11 Thursday, May 10, 2012 6:45 PM Pacific Time
Register here.
MSDN Webcast: What's New with LightSwitch in Visual Studio 11 Friday, May 11, 2012 1:00 PM Pacific Time
Hope to see you there!
Last Fall I started posting a rollup of interesting community happenings, content, samples and extensions popping up around Visual Studio LightSwitch. If you missed those rollups you can check them all out here: LightSwitch Community & Content Rollups
April continued to roll out content around Visual Studio 11 Beta since it was released back on February 29th. If you haven’t done so already, I encourage you to give it a spin by downloading Visual Studio 11 Beta. Also make sure to check out these LightSwitch Beta resources and community sites:
Have an idea?: LightSwitch UserVoice site Need to report a bug?: LightSwitch Connect site Have a question?: LightSwitch Beta Forum Need to learn what’s new?: LightSwitch Developer Center
If you haven’t noticed the LightSwitch team has been releasing a lot of good content around the next version of LightSwitch in Visual Studio 11. Check out the LightSwitch Developer Center for a list of key Beta resources for you to explore. Here’s some of our more popular content:
One of the biggest features with LightSwitch in Visual Studio 11 is the Open Data Protocol (OData) support. Not only can you consume OData services in LightSwitch, the middle-tier services are also now exposed as OData service endpoints reachable by other clients. In April, the community posted many more examples of alternative clients that you can build against your LightSwitch services. I’d like to particularly thank Michael Washington who runs the www.LightSwitchHelpWebsite.com who has been on fire this month posting most of these. Awesome!
One of our other LightSwitch community rock stars started a new LightSwitch column in MSDN Magazine in March. Jan van der Haegen continues his journey into the depths of LightSwitch with his second article in the April issue:
Leading LightSwitch: The LightSwitch MVVM Model In this month’s Leading LightSwitch column, Jan explains MV3, a variation of the MVVM application architecture used for LightSwitch apps that is even more powerful than the original application architecture.
Paul Ferrill released his new book in the beginning of April on building SharePoint Apps with LightSwitch. It sounds like this is a short book for the LightSwitch beginner looking to connect to SharePoint data.
Also released was Pro Visual Studio LightSwitch 2011 Development by Tim Leung and Yann Duran. You may have seen these guys helping answer questions in the LightSwitch forums and they really know their stuff.
More LightSwitch books to check out:
In April Xpert 360 released a FREE LightSwitch extension that allows you to connect to Dynamics CRM. Looks like they are also working on one for connecting to Salesforce. Check out these resources to get started:
Many of our Visual Studio partners who build LightSwitch extensions injected into the #LightSwitch twitter feed this month to remind us of these great products, some with new features recently added.
Join me Friday May 11th 1:00 PM PST for What's New with LightSwitch in Visual Studio 11.
Microsoft Visual Studio LightSwitch is the simplest way to build business applications and data services for the desktop and the cloud. LightSwitch contains several new features and enhanced capabilities in Visual Studio 11. In this demonstration-heavy webcast, we walk through the major new features, such as creating and consuming OData services, new controls and formatting, new features with the security system and deployment, and much more.
Extensions (see all 85 of them here!):
In addition to the above, we had a few more extensions from the community released this month.
Samples (see all 80 of them here):
Team Articles:
Lots more articles from the team this month on all the new features in LightSwitch in Visual Studio 11.
We also had a couple top requested How To posts that apply to all versions of LightSwitch:
Community Content:
Become a fan of Visual Studio LightSwitch on Facebook. Have fun and interact with us on our wall. Check out the cool stories and resources. Here are some other places you can find the LightSwitch team: LightSwitch MSDN Forums LightSwitch Developer Center LightSwitch Team Blog LightSwitch on Twitter (@VSLightSwitch, #VisualStudio #LightSwitch)
Note: This information applies to LightSwitch in Visual Studio 11 (LightSwitch V2)
In business applications sometimes we need to flag records with additional attributes in response to business rules and then consistently filter those flagged records in some way or another throughout the application. For instance we may have critical or historical data that must always be stored in our databases and never deleted. I used to work in the health care industry and it was important to keep historical patient data. Therefore we would not allow a user to delete a patient’s hospital visit information from the system. Over time, however this causes our data sets to get very large and distracts users from finding the relevant information they need. Hence, we need a way to flag these records and then filter this data out of our result sets across the entire application.
Last year I wrote an article based on LightSwitch in Visual Studio 2010 (LightSwitch V1) showing how you can use the Save & Query pipeline to archive and filter records instead – effectively marking them deleted but not actually deleting them from the system: Using the Save and Query Pipeline to “Archive” Deleted Records. With LightSwitch in Visual Studio 11 (LightSwitch V2) the filtering mechanism has been improved using the new entity set filters.
In this post I’ll show you how to use the new entity set filter methods to apply global filtering of records. But first, let’s recap how we can flag these records using the save pipeline.
The save pipeline runs in the middle tier anytime an entity is being updated, inserted or deleted. This is where you can write business logic that runs as changes are processed on the middle tier and saved to data storage. Let’s take an example where we don’t want to ever physically delete customers from the system. Here’s our data model for this example. Notice that I’ve created a required field called “IsDeleted” on Customer that is the type Boolean. I’ve unchecked “Display by Default” in the properties window so that the field isn’t visible on any screens.
In order to mark the IsDeleted field programmatically when a user attempts to delete a customer, just select the Customer entity in the data designer and drop down the “Write Code” button and select Customers_Deleting method.
Here are the 2 lines of code we need to write:
Private Sub Customers_Deleting(entity As Customer) 'First discard the changes, in this case this reverts the deletion entity.Details.DiscardChanges() 'Next, change the IsDeleted flag to "True" entity.IsDeleted = True End Sub
Notice that first we must call DiscardChanges in order to revert the entity back to it’s unchanged state. Then we simply set the IsDeleted field to True which puts the entity into a change state. So the appropriate save pipeline methods (Customers_Updating & Customers_Updated) will now run automatically. You can check the state of an entity by using the entity.Details.EntityState property.
This save pipeline code remains unchanged from LightSwitch V1. However in LightSwitch V2, we need to filter the data differently. Let’s see how.
Now that we’re successfully marking deleted customers, the next thing to do is filter them out of our queries so that they don’t display to the user on any of the screens they work with. In LightSwitch V2 a new query interception method, EntitySet_Filter, has been added which allows you to specify a filter that is applied whenever an entity set is referenced. (See the recent article on the LightSwitch Team Blog by Michael Simons: Filtering Data using Entity Set Filters for details on this new feature.)
So instead of using the Customers_All_PreprocessQuery like we had to in LightSwitch V1 as demonstrated here, we can apply the IsDeleted filter in the Customers_Filter method. Using the entity set Filter method is preferred over the All_PreprocessQuery method because the Filter method will execute any time the entity set is referenced, even when the entity has relationships and is not the direct target of a query. This enables true row level filtering across the application.
So for this example, select the Customer entity in the data designer and drop down the “Write Code” button and select Customers_Filter method.
Here we need to write a filter predicate as a lambda expression.
Private Sub Customers_Filter(ByRef filter As Expressions.Expression(Of Func(Of Customer, Boolean))) filter = Function(c) c.IsDeleted = False End Sub
These expressions can seem a little tricky at first but they just take some practice. You can think if these as in-line functions. This one takes a customer parameter and then you return a Boolean expression used to filter the records. You can filter on anything you want, even filter based on security permissions like Michael showed in his blog post. (For more information on lambda expressions see: Lambda Expressions (Visual Basic) and Lambda Expressions (C#).)
Now that we’ve got our Save and Query pipelines set up to handle the “deleted” Customers, we can run the application. When a user deletes a Customer, the behavior is exactly the same as if the Customer was physically deleted from the database.
And if we peek inside the actual Customer table in the database you can see them flagged correctly.
Also, now when we write a query where Customers is not the direct target, the row filtering will still apply. For instance, we have a parent table called Regions. If we wanted to create a query “Regions Over 10 Customers” we would write our query like so:
Private Sub RegionsOver10Customers_PreprocessQuery(ByRef query As IQueryable(Of Region)) query = From r In query Where r.Customers.Count > 10 End Sub
In LightSwitch V1 the additional filter in the Customers_All_PreProcessQuery would not be called when we executed this query. It would include the count of the Customers flagged IsDeleted – which isn’t what we want. You would have to include that filter in this query as well. So if you had a lot of queries in your application that indirectly reference the Customer, then this could get difficult to maintain. In LightSwitch V2 the Customers_Filter method is always called anytime the Customer entity set is referenced, regardless if it is the direct target of a query or not, so this query would always return the expected results.
Because we want to encourage using this approach to achieve true row level filtering, for new LightSwitch V2 projects there is no entry point for EntitySet_All_PreProcessQuery methods anymore. With upgraded projects from V1 they will still run the same as before and you will see them as modeled queries in the Solution Explorer. So there are no breaking changes to your application, but you will want to strongly consider using the entity set Filter methods instead.
I hope this post has demonstrated how powerful and simple LightSwitch can be when working with data in the save and query pipelines. We’ve beefed up the global filtering technique so that it can handle scenarios like I showed above as well as row level security scenarios Michael demonstrated. If you were using the _All_PreProcessQuery methods, then they will continue to run when you upgrade to Visual Studio 11. However you should be using the entity set Filter methods instead for applying global filters that will run no matter how the entities are accessed.
Note: This article applies to LightSwitch in Visual Studio 11 Beta (LightSwitch V2)
In Visual Studio LightSwitch, when you design your data model through the Data Designer you are either creating new tables or attaching to external data sources. When you create new tables, LightSwitch automatically creates them in the internal database, also known as the Intrinsic database or ApplicationData. In the first version of LightSwitch in Visual Studio 2010 we used SQL 2008 Express for the internal database development. Now with LightSwitch in Visual Studio 11 we are using SQL Server LocalDB. (Note: LocalDB is only used during development time. When you deploy your app you can choose to deploy to any version of SQL Server.)
LocalDB is the new version of SQL Server Express that has a much lower memory footprint and is targeted for developers. It is installed automatically when you install Visual Studio 11. When developing LightSwitch projects, LocalDB is used in place of the SQL Server Express user instance feature (which is now deprecated). In this post I’ll show you some tricks on working with LocalDB databases in LightSwitch projects.
In Visual Studio 2010 you used the Server Explorer to access your SQL Express databases. Server Explorer still exists in Visual Studio 11, but there is a new window called the SQL Server Object Explorer that you can use to work with your LocalDB. SQL Server Object Explorer provides a view of your database objects that’s similar to SQL Server Management Studio.
To connect to your LocalDB click the “Add SQL Server” button on the toolbar to bring up the connection dialog. The server name is: (localdb)\v11.0
Once you debug (F5) your LightSwitch project the first time, the internal ApplicationData database will show up under the Databases node. LocalDB will auto attach to the database the first time it is accessed.
IMPORTANT NOTE: If you are developing only new tables in a LightSwitch project, you should never need to use this window because you model your data through the LightSwitch Data Designer. In fact, if you modify the schema of the internal database outside of the Data Designer, then the LightSwitch model will get out of sync and you will get errors running the application. I REPEAT, DO NOT MODIFY YOUR INTERNAL DATABASE OUTSIDE THE LIGHTSWITCH DATA DESIGNER.
However, the SQL Server Object Explorer is very handy for working with external databases that you want to bring into your LightSwitch application. During development it is common to work with a local copy of your external databases and SQL Server Object Explorer is a handy way to manage these. One of my favorite features is the schema compare. For more information on the capabilities of the SQL Server Object Explorer please see: What's New for Data Application Development in Visual Studio 11 Beta
Keep in mind that external databases are just that -- they are external to LightSwitch. So you must manage their schema and deployment completely outside of the LightSwitch development environment. For more information on connecting to external data sources see - How to: Connect to Data
With a lot of samples out there in all sorts of versions of SQL Server this feature comes in handy: you can attach to a database file (.MDF) and it will automatically upgrade your database to the current version and attach it to your LocalDB instance. This makes it easier to connect to and develop against external databases in LightSwitch. (Note that if you upgrade the database, it will no longer be compatible with earlier versions of SQL Server.)
Let’s take an example.
The AdventureWorks family of sample databases are used in many modern database examples from Microsoft today. They show off features of the latest versions of SQL Server and are maintained on CodePlex. You can download them here. There is a simpler database included here called AdventureWorksLT (AdventureWorks “Light”) that is better for developers learning data since it has a simpler schema.
To attach the AdventureworksLT database:
USE [master] GO CREATE DATABASE [AdventureWorksLT] ON ( FILENAME = N'C:\Data\AdventureWorksLT2012_Data.mdf' ) FOR ATTACH ; GO
Using the SQL query editor you can also execute other SQL scripts to create and work with your databases. However, you can also use the Server Explorer to attach to a database using a wizard which was also available in Visual Studio 2010. For more information see - How to: Connect to a File-based Database.
Once you have your databases attached, it’s easy to add them as an external data source.
The LightSwitch Data Designer will not allow you to change the underlying schema of an external data source. Instead, you can use SQL Server Object Explorer (or any other favorite database tool) to make changes. When you modify the schema of your external data source you need to bring those changes back into LightSwitch (remember do not modify your internal database this way).
To sync the changes, from the Solution Explorer right-click on the external data source and select “Update Datasource”.
Choose all the tables you are using in your LightSwitch application and then click Finish and the changes will be reflected back in the Data Designer.
SQL Server LocalDB uses less memory than previous versions of SQL Server Express and still provides the automatic attach of databases in order to speed up development of your data-based projects. For external databases, the SQL Server Object Explorer is a welcome addition to Visual Studio and has a similar experience to SQL Server Management Studio. However, remember that you should only make changes to your internal database (ApplicationData) via the LightSwitch Data Designer.
When working with the internal database in LightSwitch, LocalDB is only used during development time. When you deploy your app that uses the internal database, you can choose to deploy to any version of SQL Server, including SQL Azure. Additionally, if you are using external data sources in your LightSwitch application, you are asked for the connection strings of the production databases upon deploy. For more information on deploying LightSwitch applications see Deploying LightSwitch Applications in the MSDN Library and my post LightSwitch IIS Deployment Enhancements in Visual Studio 11.
One of the biggest features with LightSwitch in Visual Studio 11 is the Open Data Protocol (OData) support. OData is a standard Web protocol for exchanging data on the web which provides easy, secure access into data stores. Not only can you consume OData services in LightSwitch, the middle-tier services are also now exposed as OData service endpoints reachable by other clients. For instance, I showed how power users can easily perform analytics and reporting on your LightSwitch data using Excel PowerPivot.
However, this also allows you to create a different UI for your LightSwitch application so that you can expose it to other platforms that aren’t supported out of the box. Furthermore, all your business rules and access control logic is preserved when calling these services. Your data models, business logic, and access control logic is where you spend the bulk of your time when building a LightSwitch application and all this work is preserved.
The team has been focusing on the architecture of these services in LightSwitch as well as how to use them. Particularly:
The community has taken these examples even further. I’d like to call out Michael Washington who runs the www.LightSwitchHelpWebsite.com where he’s been on fire recently posting examples of companion clients. Check these out!
Jan van der Haegen also wrote a great MSDN Article last month using a WIndows Phone 7 client:
Consume a LightSwitch OData Service from a Windows Phone application
Opening up the middle-tier services was a major goal for LightSwitch and you can see why – it allows you to exchange data easily with other systems and clients over the Web. I’m excited to see what the community comes up with next!
Join me next month as I take you on a tour of the new features of LightSwitch in Visual Studio 11.
Friday, May 11, 2012 1:00 PM Pacific Time
Hope you can join this webcast, it should be a lot of fun! In the meantime, enjoy some of these LightSwitch in Visual Studio 11 resources.
Articles:
Featured Extensions:
Featured Samples:
Community:
You can find all of this plus more on the LightSwitch Developer Center.
That should keep you busy until the webcast next month
March was filled with a flurry of content around Visual Studio 11 Beta since it was released on February 29th. If you haven’t done so already, I encourage you to download it and give it a spin.
You can provide general feedback using the Visual Studio UserVoice site and LightSwitch-specific feedback on the LightSwitch UserVoice site. There are also a handful of Beta forums you can use to ask questions in particular areas, including the LightSwitch in Visual Studio 11 Beta Forum.
If you haven’t noticed the LightSwitch team has been releasing a lot of good content around the next version of LightSwitch in Visual Studio 11. We’ve created a page on the LightSwitch Developer Center with a list of key Beta resources for you. Check back to the page often as we add more content each week! Here’s the easy-to-remember URL:
In March the team released the beta version of the LightSwitch Cosmopolitan Shell and Theme extension for Visual Studio 11 Beta.
We drew inspiration from the Silverlight Cosmopolitan theme in designing the extension. The shell and theme provide a modern UI to achieve a more immersive feel, simple and clean styling for the controls, corporate/product branding, as well as many other improvements. This shell will become the default shell for new LightSwitch projects developed with Visual Studio 11. Check out these screen shots and give it a spin! (click to enlarge). You can provide feedback and report issues with the shell in the Beta forum or directly on the LightSwitch Team blog post.
An updated version of the LightSwitch Extensibility Toolkit for Visual Studio 11 Beta was also released in March. This toolkit refresh provides project types for creating new LightSwitch Extension Libraries using Visual Studio 11 beta and includes templates for creating all the different types of supported LightSwitch extensions. If you’re building LightSwitch extensions then you’ll want to check out this release.
Along with this release are updated versions of all the extensibility samples.
If you’ve been spending any time developing LightSwitch applications and listening to the #LightSwitch hash tag on twitter, hanging out in the forums, or searching the internet for LightSwitch content, then you probably have run across these people at one time or another. These folks constantly pop up in our community channels – some have been helping the LightSwitch community since the early betas and some are emerging recently. These are just a few of the LightSwitch rock stars to definitely keep an eye on.
Have more folks to recommend? Post a comment below!
One of our LightSwitch rock stars has started a new column on MSDN Magazine! Jan van der Haegen released his first “Leading LightSwitch” column in the March issue. I’m really looking forward to the great stuff Jan will teach us!
Consume a LightSwitch OData Service from a Windows Phone Application Jan Van der Haegen's first LightSwitch column explores one of the key features added in the beta release of the tool--the ability to create and consume OData services, which can in turn be consumed from any client, including custom Windows Phone applications.
Lots of content has been streaming out from folks all over the internet. I’m also excited by the number of extensions the community released this month, nice! Here’s some more notable resources I found.
Extensions (see all 81 of them here!):
More Samples (see all of them here):
Visual Studio 11 Beta (LightSwitch V2)
Visual Studio LightSwitch (LightSwitch V1)