Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
        x1 = e.X
        y1 = e.Y
    End Sub
 
    Private Sub PictureBox1_MouseMove(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove
        If e.Button = Windows.Forms.MouseButtons.Left Then
            x2 = Nothing
            y2 = Nothing
 
            Dim g As Graphics = Me.PictureBox1.CreateGraphics
            PictureBox1.Refresh()
            If e.X < x1 Then
                If e.Y < y1 Then
 
                Else
 
                    g.DrawRectangle(Pens.Black, e.X, y1, x1 - e.X, e.Y - y1)
                End If
            Else
                g.DrawRectangle(Pens.Black, x1, y1, e.X - x1, e.Y - y1)
            End If
            g.Dispose()
        End If
    End Sub
 
    Private Sub PictureBox1_MouseUp(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseUp
        x2 = e.X
        y2 = e.Y
 
        ' Wenn Rechteck verkehrt gezeichnet
        If x2 < x1 Then
            x2 = x1
            x1 = e.X
        End If
 
        PictureBox1.Refresh()
    End Sub

fg viperbone