I just found a really cool nice tip on http://www.devx.com/tips/dot-net/quick-way-to-disable-copy-paste-170320075010.html.
In the old versions of .NET, we needed to override the default context menu and override the ProcessCmdKeyfunction to return True to disable Copy-Paste of content into textboxes through keys such as Ctrl+C, Ctrl+V, Shift+Insert, etc.In the newer versions of .NET, we can just disable the "ShortcutsEnabled" property to False. This will do the trick. You can no longer copy/paste or perform any other actions through shortcuts on the textbox.
In the old versions of .NET, we needed to override the default context menu and override the ProcessCmdKeyfunction to return True to disable Copy-Paste of content into textboxes through keys such as Ctrl+C, Ctrl+V, Shift+Insert, etc.
ProcessCmdKey
In the newer versions of .NET, we can just disable the "ShortcutsEnabled" property to False. This will do the trick. You can no longer copy/paste or perform any other actions through shortcuts on the textbox.