Public Class Form1
    Private r1 = New Rectangle(50, 100, 50, 50)
    Private r2 = New Rectangle(180, 100, 50, 50)
 
    Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown
        If r1.Contains(e.Location) Then MsgBox("Rote Bitmap")
        If r2.Contains(e.Location) Then MsgBox("Blaue Bitmap")
    End Sub
 
    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        e.Graphics.FillRectangle(Brushes.Red, r1)
        e.Graphics.FillRectangle(Brushes.Blue, r2)
    End Sub
End Class