Public Class Form1
 
    Declare Auto Function SetCapture Lib "user32.dll" (ByVal hwnd As Integer) _
      As Integer
    Declare Auto Function GetCapture Lib "user32.dll" () As Integer
    Declare Auto Function ReleaseCapture Lib "user32.dll" () As Integer
    Declare Auto Function SetFocusWnd Lib "user32.dll" Alias "SetFocus" (ByVal _
      hwnd As Long) As Integer
 
    Declare Auto Function GetActiveWindow Lib "user32.dll" () As Integer
    Declare Auto Function GetLastError Lib "kernel32.dll" () As Integer
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
 
        Me.Text = GetActiveWindow
        Dim mRückgabe As Integer
        Dim mFehlercode As Integer
        mRückgabe = SetCapture(GetActiveWindow)
        mFehlercode = GetLastError
 
        Label2.Text = "Letzter Fensterhandle: " & mRückgabe
 
        Label3.Text = "Fehlercode: " & mFehlercode
 
    End Sub
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button2.Click
 
        Me.Text = GetCapture
        ReleaseCapture()
 
    End Sub
 
    Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
 
        Label1.Text = Val(Label1.Text) + 1
 
    End Sub
 
End Class