获取父ShapeContainer的子LineShape

Question

When I create a pair of LineShape and ShapeContainer objects, I make the ShapeContainer the parent using the code:

 myLS.Parent = mySC
 Me.Controls.Add(mySC)

Next, whenever the cursor position is near the end of the LineShape, I need to change the color of the line, and have started to implement the following code:

        Dim ClickedShapeContainerName As String = sender.Name
        Dim siSCId As Integer
        Dim myLS As New LineShape
        Dim mySC As New ShapeContainer
        'get ID of clicked ShapeContainer
        For Each c As Control In Me.Controls
            If c.Name = ClickedShapeContainerName Then
                mySC = CObj(c)
                If mySC.HasChildren Then
                    myLS =???????
                    siSCId = 1
                End If
                Exit For
            End If
        Next

        If siSCId > -1 Then
            If MouseIsNearBy(myLS.EndPoint) Then
                myLS.BorderColor = Color.Red
                NearLineEndPoint = True
            End If
        End If

Private Function MouseIsNearBy(ByVal testPoint As Point) As Boolean
        testPoint = Me.PointToScreen(testPoint)
        Return Math.Abs(testPoint.X - MousePosition.X) <= HitTestDelta AndAlso Math.Abs(testPoint.Y - MousePosition.Y) <= HitTestDelta
End Function

However, I cannot determine how to get the child LineShape of the parent ShapeContainer, so that I can set my new LineShape ("myLS") equal to the one found child. The mySC is successfully set to the clicked ShapeContainer, but I can't raise the child LineShape. How can this be done?

Answer 1

You have to loop through the Shape collection, not Controls, of the ShapeContainer:

If Me.Controls.ContainsKey(clickedShapeContainerName) Then
  mySC = DirectCast(Me.Controls(clickedShapeContainerName), ShapeContainer)
  For Each ls As LineShape In mySC.Shapes
    If MouseIsNearBy(ls.EndPoint) Then
      ls.BorderColor = Color.Red
    End If
  Next
End If

You could also just subscribe to the LineShape's MouseEnter and MouseLeave events, too.

Also, ShapeContainer Class makes a special note:

Be careful that you do not create more than one ShapeContainer for each form or container; doing this may introduce unexpected behavior. If you add a design-time line or shape control to a form or container after you write code to create one programmatically, you should modify that code to use the ShapeContainer created by the designer.