stkpnl = New StackPanel
stkpnl.Children.Add(pan)
mypop = New Popup
mypop.Child = New PopupSubitem
mypop.FlowDirection = System.Windows.FlowDirection.LeftToRight
Dim brd As New Border
brd.BorderBrush = New SolidColorBrush(Colors.Black)
brd.BorderThickness = New Thickness(5.0)
brd.Background = New SolidColorBrush(Colors.Black)
brd.Height = 800
brd.Width = 480
brd.Child = stkpnl
mypop.Child = brd
mypop.VerticalOffset = 250
mypop.HorizontalOffset = 0
mypop.IsOpen = True
我遇到的问题是这段代码
An exception of type 'System.InvalidOperationException' occurred in System.Windows.ni.dll but was not handled in user code
Additional information: Element is already the child of another element.