Trouble accessing the clipboard.

[HiPhiSch]

Hi all!

I tried to access the Clipboard in the OnRender section with this:

IDataObject idat;
lock(this) {
idat = Clipboard.GetDataObject();
}
// idat == null <- this happens every time

I used a try block before, the simplified code is just for testing. There is no exception thrown, but I always just get the null, no matter what is stored inside of the clipboard. I also included a demand for UIPermission including AllClipboard. This does not help. I am using VS2008 pro if that matters.

Is it somehow possible to read content from the clipboard?

I hope you can help me out.

[Simon Brown]

Try doing so from either the dialog or OnSetRenderInfo() - i've had problems before accessing the clipboard while another thread in the process is running.

[Rick Brewster]

You can only access the clipboard from an STA thread. I ran into this with some refactoring of the regular Edit->Paste command, in fact.

IDataObject idat = null;
Exception threadEx = null;
Thread staThread = new Thread(
   delegate
   {
       try
       {
           idat = Clipboard.GetDataObject();
       }

       catch (Exception ex) 
       {
           threadEx = ex;            
       }
   });
staThread.SetApartmentState(ApartmentState.STA);
staThread.Start();
staThread.Join();
// at this point either you have clipboard data or an exception

You probably also have to query the existence of clipboard data within that STA thread, btw.

And, also, don't do this from OnRender(). Do it within OnSetRenderInfo().

[BoltBait]

Man! I've been wondering about this for a while now...

Good info. Thanks!

[Rick Brewster]

Yeah the clipboard is tied in to some COM voodoo. COM objects are tied in to STA vs. MTA stuff.

[HiPhiSch]

Thanks a million! I will try it out