DragDrop registration did not succeed

Question

System.InvalidOperationException: DragDrop registration did not succeed. ---> System.Threading.ThreadStateException:

What does this except

Answer 1

function abc
{
            Thread t = new Thread(new ThreadStart(xyz));
            t.SetApartmentState(ApartmentState.STA);
            t.Start( );    
}
function xyz
{
 the code of Windows form..or whatever which is causing the error
}