ASP.NET Server Controls in VS 2008 and .NET 3.5 and Sharepoint

Today is going to be a bit of a rant. Background on the issue is that in VS 2005 I have written server controls for ASP.NET and Web Parts for Share Point. Typically for building Share Point web parts I like to developement them as server controls to so I have this nice easy structure to work with until I have something that does basically what I want. The trick with a server control is basically basic C# stuff. First you make a class and inherit from your base control and then you overwrite a method and add some declaritive stuff and then you can use it on your page by using a register in the ASPX. Then you can use your tag to create an instance of your control. Also this can then be put into its own dll and added to VS's toolbar and you can pass the dll around to friends etc and everyone can have this cool dll. Now to turn the control into a web part basically you change the base class, add a few using statements and change the output method name, make sure its all in a dll and your good. So far so good right?
For a server control, the class basically looks like this:

[ToolboxData("<{0}:SomeName id=\"\" runat=\"server\" />")]
public class SomeName: System.Web.UI.WebControls.WebControl
{ protected override void Render(HtmlTextWriter writer)
{
writer.Write(PresentHTML()); // some method we make...
}
}

We also add a few bindable properties like id or width or title or something that might look like this:

private string _Id = string.Empty;

[Bindable(true), Category("Appearance"), DefaultValue("")]

public string id
{
get
{ return _Id;
}
set
{ _Id = value;
}
}

Again straight forward stuff. right? We also might add other functionality of course and we have it in a name space but this is the key bits above. Now to turn this into a 'WebPart' we make it look something like this:

[DefaultProperty("Text"),
ToolboxData("<{0}:MyWebPart runat=server>"), XmlRoot(Namespace = "MyWebPart")]
public class MyWebPart : WebPart
{
private string _Id = string.Empty;
[Bindable(true), Category("Appearance"), DefaultValue("")]

public string id
{
get
{ return _Id;
}
set
{ _Id = value;
}
}

protected override void RenderWebPart(HtmlTextWriter writer)
{
writer.Write(PresentHTML()); // our private method that does the real work...
}
}
not a big change and again pretty straight forward. I dont' show all the properties and methods like the one reference to 'PresentHTML' which is just a private method that returns a string. This is the basic stuff needed for sharepoint. The one other thing is to make sure you have the using statements that reference all our Sharepoint bits:

using Microsoft.SharePoint.Utilities;
using Microsoft.SharePoint.WebPartPages;
using Microsoft.SharePoint.WebControls;

and of course the sharepoint dll that your building to needs to be referenced. So to use the server control version you have to create a Register tag in your ASP.NET that looks like this:

<%@ Register TagPrefix="prefix" Namespace="ControlNameSpace" %>

then in the ASPX page we can add the tag for our control to test it without all the jumping around you need todo with Share Point. In this case it might look like this:

This is 'All Good' in VS 2005 but the other day (earlier this morning) I had to make it work in VS 2008 for embededing a webpart 'Silverlight' control into Sharepoint. So I got to the test page of the silverlight project and do basically the above and make a web part that writes out all my Silverlight stuff (actually it was Devin's Silverlight app). This way we care wire up bits that the web part needs to pass into the Silverlight class todo its thing for when it actually has to live in Sharepoint. I would have thought this easy enough...

So I add the class and set it up as a server control. I add the references, and the register for the tag prefix and namespace reference and then add a tag to the control that should create the silverlight app. I compile it and try to run it and it blows up entirely. After fighting with this for some time it turns out that you need to have an 'Assembly' reference in the register tag in VS 2008/.NET 3.5 for a server control to be able to run in ASP.NET 3.5. So then it looks something more like this:

<%@ Register TagPrefix="prefix" Namespace="ServiceNamespace" Assembly="SilverlightApp" %>

The part that bothered me is that if the class is in the same assembly as the rest of the site and we call out the name space and class specifically it should be able to find the default assembly since its run in that assembly... but alas I was wrong. Not that, that is a surprise but it always seems to surprise me when I am. :)