C# Winforms - change cursor icon of mouse

Try to do the following:

System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.WaitCursor;

More information is available at Cursors Class documentation

Cursor class doesn't support GIF files or animated cursors (.ANI). You can load a custom cursor doing

Cursor.Current = new Cursor("C:\\ic.cur");

Maybe you can convert yout GIF file to cursor format using a tool like Microangelo. In addition, there is another thread related to it.

How do you convert a GIF into a CUR file?