Public Class Form1
    Declare Auto Function FindWindow Lib "user32" (ByVal lpClassName As String, _
      ByVal lpWindowName As String) As IntPtr
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
    System.EventArgs) Handles Button1.Click
        Dim hwnd As IntPtr = FindWindow(Nothing, "Form1")
        MsgBox(Me.Handle.ToString & ", " & hwnd.ToString)
    End Sub
End Class