wpf - CLIPBRD_E_CANT_OPEN error when setting the Clipboard from .NET

Question

Why does the following code sometimes causes an Exception with the contents "CLIPBRD_E_CANT_OPEN":

Clipboard.SetText(str);

This usually occurs the first time the Clipboard is used in the application and not after that.

Answer 1

This is caused by a bug/feature in Terminal Services clipboard (and possible other things) and the .NET implementation of the clipboard. A delay in opening the clipboard causes the error, which usually passes within a few milliseconds.

The solution is to try multiple times within a loop and sleep in between.

for (int i = 0; i < 10; i++)
{
    try
    {
        Clipboard.SetText(str);
        return;
    }
    catch { }
    System.Threading.Thread.Sleep(10);
}