Private Declare Function IntersectRect Lib "user32" (lpDestRect As RECT, _
  lpSrc1Rect As RECT, lpSrc2Rect As RECT) As Long
 
Private Type RECT
  Left As Long
  Top As Long
  Right As Long
  Bottom As Long
End Type
 
Private oldX As Single
Private oldY As Single
Private StartX As Single
Private StartY As Single
Private Auswahl() As String
 
Private Sub Form_Load()
  Me.AutoRedraw = True
  Me.DrawStyle = vbDot ' oder vbDashDotDot oder vbDash oder vbDashDot
End Sub
 
Private Sub Form_MouseDown(Button As Integer, Shift As Integer, X As Single, Y _
  As Single)
  StartX = X
  StartY = Y
  oldX = StartX
  oldY = StartY
  Me.Cls
End Sub
 
Private Sub Form_MouseMove(Button As Integer, Shift As Integer, X As Single, Y _
  As Single)
Dim sm As Integer
 
  If Button = 1 Then
    sm = Me.DrawMode
     Me.DrawMode = vbInvert
      Me.Line (StartX, StartY)-(oldX, oldY), , B
       Me.Line (StartX, StartY)-(X, Y), , B
      oldX = X
     oldY = Y
    Me.DrawMode = sm
  End If
 
End Sub
 
Private Sub Form_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As _
  Single)
Dim C As Control
Dim E1 As RECT
Dim E2 As RECT
Dim E3 As RECT
Dim Zähler As Long
 
  E1.Left = IIf(StartX < oldX, StartX, oldX)
  E1.Top = IIf(StartY < oldY, StartY, oldY)
  E1.Right = IIf(oldX > StartX, oldX, StartX)
  E1.Bottom = IIf(oldY > StartY, oldY, StartY)
 
  Me.Cls
 
  For Each C In Me
    If Not C.Name = "Timer1" Then
      E2.Left = C.Left
      E2.Top = C.Top
      E2.Right = C.Left + C.Width
      E2.Bottom = C.Top + C.Height
      IntersectRect E3, E1, E2
        If E3.Left > 0 Then
          Me.DrawWidth = 5
           Me.Line (E2.Left, E2.Top)-(E2.Right, E2.Bottom), vbRed, B
            Me.DrawWidth = 1
            ReDim Preserve Auswahl(Zähler)
           Auswahl(Zähler) = C.Name
          Zähler = Zähler + 1
        End If
    End If
  Next
 
  If Zähler > 0 Then
    ReDim Preserve Auswahl(Zähler - 1)
      For N = 0 To UBound(Auswahl)
        MsgBox Auswahl(N)
      Next
  End If
 
End Sub