Error:

Unable to cast object of type ‘System.Collections.Generic.List`1[EditQuoteController+UnsavedQuoteItemInfo]’ to type ‘System.Collections.Generic.List`1[EditQuoteController+UnsavedQuoteItemInfo]’.

Yes, you read that right.  Unable to cast object of type X to type X.

I have seen this type of error once before and it was when there were multiple assemblies referencing different version of a common assembly, so even though their names were the same, their versions were different.

But in this instance there is nothing like this that could be having an impact.  All of the classes of consequence are in the same assembly.

Also, I don’t get exception very often, only every now and then.

UPDATE:

I think maybe this is happening between builds on my development machine b/c I am storing some data in the session.  So the version in session was from the last build?  Doesn’t sound like a great explanation, but it’s the best I have at this point.

UPDATE 2:

I am pretty sure that what I wrote in the last update is what is actually happening. 

I used this code:

Try
    list = CType(view.Session.Item(Me.UnsavedKey), List(Of UnsavedQuoteItemInfo))
Catch ex As System.InvalidCastException
    Dim sError As String = "Unable to cast from type " & _
        view.Session.Item(Me.UnsavedKey).GetType.AssemblyQualifiedName & _
        " to type " & GetType(List(Of UnsavedQuoteItemInfo)).AssemblyQualifiedName & _
        ".  The session has been cleared."
    view.Session.Item(Me.UnsavedKey) = Nothing
    Throw New System.ApplicationException(sError)
End Try

Which producted the following 2 types:

System.Collections.Generic.List`1[[EditQuoteController+UnsavedQuoteItemInfo, App_Web_bp-bbqew, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null]], mscorlib, Version=2.0.0.0, Culture=neutral PublicKeyToken=b77a5c561934e089

System.Collections.Generic.List`1[[EditQuoteController+UnsavedQuoteItemInfo, App_Web_ve7ziow-, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null]], mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089. 

I am guessing this is a by product of using the web site project, instead of web application project.  There are some other reasons why we wanted to use web site instead of web app on this project, so you don’t have to scold me: we made the right choice.

But it seems that every time I make a change to the project, it creates a new dynamically named assembly.  So even though the classes are really the same, they are globally different as far as asp.net is concerned.

Rob Howard has a nice article on how to use the 301 redirect (permanent redirect) in order to get search engines to spider the new page, as opposed to just using Response.Redirect, which will send a 302 (temporary redirect) to the client.

These are some nice looking, cross browser compliant, ASP.NET based, free controls from Obout.com

Flyout can perform stuff like this:

But almost more interesting is how it can be used in conjunction with traditional controls.  For example, you can wire up a nice looking “Alt Text” effect for images and labels, and you can provide some nice explanation in the flyout for how to properly fill in a control.  The example they give on their site shows a textbox for “Routing Number” and when you click on the textbox it shows this in the flyout:

The alternating content control which is called “Show” (Show examples) can rotate through some content like so:

These are both free controls.  Very nice!

I recently ran into an interesting problem… my webservice application seemed unable to read info from the web.config file.

I tried adding some invalid < marks to the config file and the app still ran w/o any error (but still wouldn’t read the web.config appSettings or connectionString sections).

So I created another IIS application and it worked as expected.

So I deleted the troubled IIS App and recreated it.  Still broken!

The solution was to clear out the ASP.NET Temporarly Files folder in c:windows……

Once that was gone, and I restarted IIS, everything went back to normal.

You’ve probably seen this one.

Whenever you do one of the following:

Response.End()
Response.Redirect("page.aspx")
Server.Transfer("page.aspx")

You end up with a ThreadAbortException, “Thread was being aborted”.

I had previously dealt with this by swallowing the ThreadAbortException, which of course isn’t a great method, but it worked.

Well today I came across a better way for all of these.

In a recent gathering of the ALT.NET group, ScottGu gave a demo of the upcoming MVC framework for asp.net.

The article (and video) can be found here.

Lots of people in the ALT community have been working with asp.net and MVC by using one of the OS frameworks out there like Monorail, but I am glad to see that MS is not sitting around waiting on this issue.

Hopefully this will make testing even easier. 

The asp.net site has a section where they are putting up short videos showing how to do things in asp.net as well as VSTS and asp.net AJAX.

You can find the site here, and the RSS feed here.

There are some similar videos started to get produced for TFS here, with an RSS feed here.