Visual Studio 2008 Design Surface Error: "The operation could not be completed. Invalid formatetc structure."

Question

In a VS2008 web site project, I have a page open in split view. I try to drag an Infragistics web control onto the page's design surface. Nothing happens. I try to drag same onto the htmlz. Dialog box with

The operation could not be completed. Invalid formatetc structure.

Subsequently the dragged control does not appear in the design surface or html.

Project compiles fine, runs fine. The error is just at at design-time.

Tried resetting the toolbox and re-adding the Infragistics controls. Cleaned project and rebuilt solution.

Help?

Further info: this is not an error specific to Infragistics (eg http://www.google.com/search?q=the+operation+could+not+be+completed.+invalid+formatetc+structure&ie=utf-8&oe=utf-8&aq=t). There are various voodoo solutions for this on other boards, but I'm never happy with a vague "I reinstalled VS and then wiped my hd and then performed a unicorn sacrifice on my keyboard then it works!" Specifics please--what type of unicorn exactly?

Further configuration info: Straight-laced VS2008 w/no SP1 or installed products. Does have hotfixes, but last ones installed a couple months ago (repro steps done many times since w/no problem).

Answer 1

The assembly reference to the control library dll is incorrect/absent in the project's web.config. Add/correct the dll reference to fix.

Answer 2

I ran into this very problem with C#-Express trying to create my first WPF app. Resetting the toolbar didn't help. This was the answer:

https://silverlight.net/forums/p/23191/82251.aspx

Two notes tho:

• First, %localappdata%\Microsoft\VisualStudio wasn't the path - it was vsexpress.
• *.tbd files were hidden, otherwise the folder looks pretty sparse!

Deleting the .tbd files and resetting the toolbar fixed it for me!

Answer 3

I have Visual Web Developer 2008 (VWDExpress) and I was having same problem on dragging and dropping Silverlight controls. Based on advise from n8wrl, I closed VWDExpress and deleted all .tbd files from C:\Documents and Settings\\Local Settings\Application Data\Microsoft\VWDExpress\9.0 folder. Started VWDExpress again and it works like charm.