shapecontainer و parent چه کاربردی دارند ؟

[roya.raha]

سلام
shapecontainer و parent چه کاربردی دارد ؟
و کلا تفسیر این سورس چیه ؟

Imports Microsoft.VisualBasic.PowerPacks
Public Class Form1
Private Sub Form1_Load() Handles MyBase.Load
Dim NewOval As New OvalShape
Dim i As Integer
Dim found As Boolean
' Loop through the Controls collection.
For i = 0 To Me.Controls.Count - 1
' If a ShapeContainer is found, make it the parent.
If TypeOf Controls.Item(i) Is ShapeContainer Then
NewOval.Parent = Controls.Item(i)
found = True
Exit For
End If
Next
' If no ShapeContainer is found, create one and set the parents.
If found = False Then
Dim sc As New ShapeContainer
sc.Parent = Me
NewOval.Parent = sc
End If
NewOval.Size = New Size(200, 300)
End Sub