Beth Massi - Sharing the goodness that is VB : ASP.NET

New Podcast Series on MisfitGeek.com

Beth Massi — Tue, 02 Jun 2009 21:09:00 GMT

Joe Stagner, ASP.NET/Web community guru, has just launched a new podcast on MisfitGeek.com. In this first episode he talks with Scott Hunter, a Senior Program Manager Lead on the ASP.NET Team, about the future of Web Forms and how Web Forms compares with ASP.NET MVC. He also talks about web data controls and compares the web forms development experience to the ease of VB6 forms development which is interesting to me.

Episode #1 - Scott Hunter on the Future of Web Forms

This Joe’s first podcast and he’s taking suggestions on how to make it better so please send him comments here.

Enjoy!

Channel 9 Interview: ASP.NET MVC using Visual Basic XML Literals

Beth Massi — Mon, 16 Feb 2009 20:20:40 GMT

I just posted an interview on Channel 9 with Dmitry Robsman, the Product Unit Manager for ASP.NET. In this interview he shows us how he implemented ASP.NET MVC views using Visual Basic's XML Literals instead of .aspx pages. Dmitry shows us how this makes coding the views much cleaner using standard OOP principals. He also makes some very interesting observations about DSLs and Visual Basic XML literals. You can download the code Dmitry shows in the interview from his blog here.

Enjoy!

ASP.NET Dynamic Data Tutorials

Beth Massi — Tue, 30 Sep 2008 23:41:04 GMT

Bill Burrows has released more video tutorials! This time he focuses on the ASP.NET Dynamic Data feature that is available in Visual Studio 2008 SP1. If you need to build a quick web site against a database then you should definitely check this framework out.

Also check out the Web Development section of the Visual Basic Learning page for more VB ASP.NET videos.

Enjoy!

Video Tutorials on ASP.NET Model-View-Controller (MVC) Framework

Beth Massi — Wed, 02 Apr 2008 02:00:00 GMT

Bill Burrows, Visual Basic MVP, has done it again and is creating another series of video tutorials on the ASP.NET MVC Framework. Based on ScottGu's blog posts, Bill teaches us how to use this pattern of web development using Visual Basic. Check back often, right now Bill explains the basics and more will be added in the coming weeks.

Enjoy!

LINQ Enabled Personal Web Site Starter Kit

Beth Massi — Wed, 13 Feb 2008 19:03:00 GMT

Jim Wooley, VB MVP, has rewritten the original Personal Web Starter Kit using LINQ for the data tier rather than stored procedures and ADO.NET and has put it up onto Code Gallery. The starter kit manages images in a SQL database by album.

You can download the LINQ-enabled Personal Web Starter Kit here: http://code.msdn.microsoft.com/LinqPersonalWeb

By the way, you can see all the latest Visual Basic Code Gallery and CodePlex projects as well as Jim's ThinqLinq blog -- plus all things cool in VB on the Visual Basic Developer Center!

Enjoy!

Northwind Meets Virtual Earth - Generate VE Maps with LINQ

Beth Massi — Tue, 04 Dec 2007 02:48:00 GMT

With Visual Basic 9 and LINQ you can easily create XML from multiple data sources including relational data, other XML sources or any other queryable object. Since most modern systems interact with each other in some form of XML the possibilities are endless. SOAP, XAML, HTML, RSS can all be created easily with LINQ to XML in Visual Basic 9. For instance, what if we wanted to display all our customers in the Northwind database on a map generated by Microsoft Virtual Earth?

Virtual Earth allows you to pass it an RSS document of items specifying their latitude and longitude to easily map out multiple locations in the world. There are a couple different formats you can pass it and one is the GeoRSS standard. All we have to do is create this XML by obtaining the latitude and longitude from the addresses we have in our customers table and then pass this GeoRSS to Virtual Earth. We can grab the latitude and longitude of our customers in the United States using the service at http://geocoder.us. This service can return a set of coordinates from any US address in a variety of formats including REST-ful RDF. We can use this service in our LINQ query in order to create the GeoRSS from our customers table in the Northwind database.

Assuming you already have a connection in Server Explorer to Northwind (or another database with addresses will do), first add a new "LINQ to SQL classes" item to your project, name it Northwind.dbml and then drag the Customers table onto the designer from the Server Explorer. The next thing to do is to import the geo namespace at the top of our code file because we’ll be using it to return the location information in the geo namespace from the XML that is returned from the geocoder.us service.

Imports <xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#">

Now we can write a query to create the GeoRSS for our customers. Since the Northwind database contains mostly fictitious addresses you can change the addresses to real locations or we can select just the customers living in Oregon (OR) since there are a couple valid addresses there.

Dim db As New NorthwindDataContext

Dim geoRSS = _
<rss xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#">
    <channel>
        <title>Northwind Customer Locations</title>
        <link></link>
        <%= From Customer In db.Customers _
            Let Desc = Customer.Address & ", " & Customer.City _
            Let Address = Customer.Address & "," & Customer.PostalCode _
            Where Customer.Country = "USA" AndAlso Customer.Region = "OR" _
            Select <item>
                       <title><%= Customer.ContactName %></title>
                       <description><%= Desc %></description>
                       <%= GetGeoCode(Address).Descendants %>
                   </item> %>
    </channel>
</rss>

In this query we’re building up the GeoRSS and calling a user defined function called GetGeoCode that accepts the address of the customer and returns the latitude and longitude. Also notice that we’re using the Let keyword in the query in order to create query variables for description and address which are being used as we build the <item> elements. The GetGeoCode function will return an XElement of the location if one was found. The Descendants method on the XElement is then called back up in the query in order to place just the <geo:lat> and <geo:long> nodes into the GeoRSS.

Function GetGeoCode(ByVal address As String) As XElement
    Dim url = "http://geocoder.us/service/rest/?address=" & Server.UrlEncode(address)

    Try
        Dim geo = XElement.Load(url)

        Return <location>
                   <%= geo.<geo:Point>.<geo:long> %>
                   <%= geo.<geo:Point>.<geo:lat> %>
               </location>

    Catch ex As Exception
        Return <location></location>
    End Try

End Function

Now that we have the GeoRSS we can pass this to Virtual Earth to create our map. For example, we can just create a simple ASP.NET application and save the GeoRSS above to a session variable. The default page contains the JavaScript code we’re going to need to send the GeoRSS to Virtual Earth and a <div> section with the id=”myMap” that identifies the area to place the map on the page. Take a look at the Virtual Earth documentation for more information on the API.

<%@ Page Language="vb" AutoEventWireup="false" 
CodeBehind="Default.aspx.vb" Inherits="NorthwindVirtualEarth._Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Northwind Customers on Virtual Earth</title>
    <link href="style.css" rel="stylesheet" type="text/css" />
    
    <script type="text/javascript" 
        src="http://dev.virtualearth.net/mapcontrol/mapcontrol.ashx?v=5">
    </script>
    <script type="text/javascript">
        var map = null;
        var layerid=1;
        function GetMap()
        {
            map = new VEMap('myMap');
            map.LoadMap();   
            var l = new VEShapeLayer();
            var veLayerSpec = new VEShapeSourceSpecification(VEDataType.GeoRSS, "georss.aspx", l);
            map.ImportShapeLayerData(veLayerSpec, null);
        } 
     </script>
</head>
<body id="body" runat="server" >
   <form id="form1" runat="server">
   <h1>Northwind Customers on Virtual Earth</h1> 
   <div id='myMap' style="position: relative; width: 800px; height: 400px;">
         <asp:Label ID="lblStatus" runat="server" Text="No items found" Visible="False"></asp:Label>
   </div>
   </form>
</body>
</html>

The VB code-behind for the Default.aspx page simply checks to see if there were any <item> elements returned from our geoRSS query above and if so, dynamically adds the code to call the GetMap Javascript function in the onload event of the body.

If geoRSS...<item>.Count > 0 Then
    Session("georss") = geoRSS

    Me.body.Attributes.Add("onload", String.Format("GetMap()"))
Else
    Me.lblStatus.Visible = True
    Session("georss") = <rss></rss>
End If

Another page called GeoRss.aspx is just a blank page that simply returns the GeoRSS stored in the session variable that the JavaScript calls to get the content.

Public Partial Class GeoRSS
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim georss As XElement = CType(Session("georss"), XElement)

        Response.ContentType = "text/xml"
        Response.Write(georss.ToString())

    End Sub
End Class

The key takeaway here is that in one LINQ statement we queried over multiple data sources, the Northwind Database and the geocoder.us service, to create a single XML document that conformed to the GeoRSS standard and passed that to the Virtual Earth service to generate our map. As you can see, it's pretty easy to create XML, in this case RSS, from multiple sources with LINQ and Visual Basic 9. The code is attached.

And if you're interested in creating dynamic maps from your data using WPF, don't forget to check out Scott Wisniewski's DevCenter featured article Create Dynamic Maps with Visual Basic 9.0 and WPF.

Enjoy!

Visual Basic ASP.NET Data Tutorials

Beth Massi — Sat, 21 Apr 2007 11:58:00 GMT

Scott Guthrie has a post about some great content that's up on the www.asp.net site on Working with Data in ASP.NET. By default the Visual Basic tutorials are shown but you can also get C# versions as well.

Visual Basic ASP.NET "How-To"- style Videos

Beth Massi — Wed, 11 Apr 2007 15:26:00 GMT

One of the things I've been working on is a set of "How-To" or "How-Do-I" style videos for Visual Basic developers (more on the details of this series later ;-)). In doing my video format research I've been looking at videos on the web, in particular the ones on www.asp.net which impressed me. (I blogged before about some SQL-Sever Express videos I saw posted up there.)

Visual Basic developers writing web applications that are interested in learning ASP.NET AJAX should really check out these videos by Joe Stagner. They range from 3 to 30 minutes and provide great coverage of the AJAX control toolkit. The videos are shown using Visual Basic but there's sample code available in both VB and C#.

Enjoy!

Beth Massi - Sharing the goodness that is VB : ASP.NET

New Podcast Series on MisfitGeek.com

Channel 9 Interview: ASP.NET MVC using Visual Basic XML Literals

ASP.NET Dynamic Data Tutorials

More Videos on ASP.NET MVC

Video Tutorials on ASP.NET Model-View-Controller (MVC) Framework

LINQ Enabled Personal Web Site Starter Kit

Northwind Meets Virtual Earth - Generate VE Maps with LINQ

Visual Basic ASP.NET Data Tutorials

Visual Basic ASP.NET "How-To"- style Videos