Private Sub CmbxInType_KeyDown(sender As Object, e As KeyEventArgs) Handles CmbxInType.KeyDown
If e.KeyCode = Keys.Delete Or e.KeyCode = Keys.Back Then
e.SuppressKeyPress = True
End If
If Not (e.Control AndAlso e.KeyCode = Keys.C) Then
e.SuppressKeyPress = True
End If
End Sub
In form load use below line to disable right click on combobox
control to avoid cut/paste via mouse click.