January 2009 - Posts

• Visual Studio 2008 SP1 WPF Designer crashing on XAML files from certain projects

  I know that is a pretty specific title, but after wrestling with this problem for the last couple of days (with a break in there for a very nice weekend!) I figured I would try to put something specific enough for Google to index it and so that some poor soul might benefit from my frustration.   The WPF designer randomly crashing is not an uncommon thing – Google it and you will see that the solutions are hit and miss and somewhat black magic.  Things like – pin the toolbox when opening a file or create a new XAML file and that randomly fixes the old ones.  My is no less black magic as I have no clear explanation for it – but it worked for me.   My issue was that XAML files in certain projects would load just fine, but in certain other projects Visual Studio would crash hard.  Finally I removed the Presentation.Core and Presentation.Framework from one of the two projects that were having this problem and added them back.  And Voila! problem fixed for not only that project, but also the other one as well.  I know – random and inexplicable – but thus is the Cider designer in 2008 SP1.  Hopefully this solves your WPF designer woes as well! Technorati Tags: WPF,WPF Designer,VS2008 SP1,Cider Posted Jan 12 2009, 04:41 PM by Bryan Hinton's space: Technology

• .NET Framework Source Code to the Rescue

  On Tuesday I got a call up from a developer that was dealing with an unusual ASP.NET problem and was looking for some help.  I am not an expert with ASP.NET at all, but we booted up in a Shared View session to look at the problem (that had been stopping him for the better part of a day or two at that point).  He had sub-classed a dropdown list and was trying to use it in his site.  The new dropdown list had a read-only property added so that when set it would render as basically a label instead of as a dropdown list.  He had validated the behavior of the new control in a separate website but couldn’t get it to work in his website and he had borrowed the code along with some other code from another project that had done a similar thing within our company.  I didn’t realize the significance of that fact until later.   We tried every little hack or nuance that I could think of and it got us nowhere.  The issue was clear the render method that had been overridden for the control was not getting called, but all the other overridden events were (like OnLoad, OnUnLoad, etc….).  Why was that happening that way?  We had another sub-classed control (a textbox) that was working correctly which made things even more confusing.  So as a last straw I figured we would plug into the new feature with Visual Studio that allows you to step into the .NET Framework code and see what is happening.  So we configured our machines using the following instructions/resources – the first link is the most update to date as VS2008 SP1 seems to have added greater support for this feature than which is was launched soon after VS2008 RTM. http://msdn.microsoft.com/en-us/library/cc667410.aspx http://blogs.msdn.com/sburke/archive/2008/01/16/configuring-visual-studio-to-debug-net-framework-source-code.aspx   Then off we went – before long we were in the ASP.NET code watching as it enumerated the control list and called render on each one of the controls belonging to the page.  Surprisingly when we got to the control that was having the problem we saw that instead of calling into our render overload it was calling into a  DropDownListAdapter class that was a sub-class of a WebControlAdapter that was been injected into the process and was controlling the rendering of our control.  Now knowing where to look we found the adapter class as well as some entries into a ServerStateBrowser file registering the adapter to our custom DropDownList class.  This was code given to the developer by the other project.  That code was obviously doing things that the developer wasn’t expecting and didn’t understand (neither did I).  Obviously there is something to learn there about being wary about taking a lot of code that you probably don’t need and aren’t sure all it does.  But all is well that ends well (especially since both he and I wanted this resolved since the New Years holidays started the next day).  We could very well still be hunting without the wonderful new tool in the toolbox to reach into the Framework to see what is happening.  Next time I will break it out sooner rather than grappling in the dark for as long as we did!   Technorati Tags: Visual Studio,.NET 3.5 Posted Jan 02 2009, 01:50 PM by Bryan Hinton's space: Technology