How to find if Caps Lock turned on (Win Forms)

I have a login form which has two textboxes. Now when the username textbox gets focus i want to find out if the caps lock key is turned. Right now I am using the following code to see if it is turned on, but it doesnt work:

Code:

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If (Control.ModifierKeys And Keys.CapsLock) = Keys.CapsLock Then
            ttLogin.SetToolTip(Me.txtUsername, "Your Caps Lock key is turned On")
        End If

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Probably by using the GetKeyState API.

Or take a look here

http://weblogs.asp.net/robgruen/archive/2004/04/15.aspx