should changing the parent of a listbox change the selected index? - vb.net

Question

You wouldn’t think so, but it does when the listbox is bound to a datasource (as far as I can see).
I’ve reduced the behaviour to the code below. The "if" line toggles between loading a list via data binding and loading a list “manually” (both use the same data table). In each case I set the selected index afterwards, and then change the parent form. With manual loading, the selected index is retained, with binding it is lost. I cannot see how this makes any sense – I don't see why changing the host form should alter any property of the list. Is this a bug?
Public Class Form1
Sub main() Handles Me.Load
Dim ListControl1 As ListBox = New ListBox
ListControl1.Parent = Me
Dim dt = New DataTable
dt.Columns.Add("intColourID")
dt.Columns.Add("strName")
dt.Rows.Add({1, "Red"})
dt.Rows.Add({2, "Green"})
dt.Rows.Add({3, "Blue"})
ListControl1.ValueMember = dt.Columns(0).ColumnName
ListControl1.DisplayMember = dt.Columns(1).ColumnName
If False Then
ListControl1.DataSource = dt
Else
For i = 0 To dt.Rows.Count - 1
ListControl1.Items.Add(dt.Rows(i)("strName").ToString)
Next
End If
ListControl1.SelectedIndex = 2
Dim z As Form = New Form
ListControl1.Parent = z
z.Show()
End Sub
End Class

Answer 1

The correct way of adding a control to a form is not to set its parent, but to add it to the Controls collection of the form. If I do it like this I do not get an exception (the three last lines commented out as you write in your comment).
Me.Controls.Add(ListControl1) ' Instead of ListControl1.Parent = Me