![]() ![]() Return CType(tvi.GetValue(ExpandedProperty), Boolean) Public Shared Function GetExpanded(tvi As TreeViewItem) As Boolean New UIPropertyMetadata(False, AddressOf ViewModelChanged)) Public Shared ReadOnly ExpandedProperty As DependencyProperty = Public Property Children As New ObservableCollection(Of Data0) RaiseEvent Propert圜hanged(Me, New Propert圜hangedEventArgs(propName)) ![]() Public Event Propert圜hanged As Propert圜hangedEventHandler Implements INotifyPropert圜hanged.Propert圜hangedįriend Sub OnPropChanged( Optional propName As String = "") Public Property IsExpanded As Boolean = False Public ReadOnly Property Items As ICollectionView Private col As New ObservableCollection(Of Data0) If child data included only one dummy data object the real child data will be loaded. The demo uses attached property (for TreeViewItem) to catch the Expanded event. At first instead of child data dummy data will be included. ![]() net knowledge to follow.Ĭan someone give an example of that, or point me to one? I imagine it's implemented something like INotifyPropert圜hanged but I've not manged to find a good example that's simple enough for my newbee. Does it get implemented on the ViewModel or on the ObservableCollection, or both? #Clarify questions codeTrue? VisualStudio (amazingly!) will add code designed to help with this but I'm not sure where to start. It appears I have to implement the INotif圜ollectionChanged interface. Now, ObservableCollection states: "Represents a dynamic data collection that provides notifications when items get added, removed, or when the whole list is refreshed." But that doesn't seem to really be the case as the child items added to the data don't show in the UI. That is working fine but the new child items do not show in the TreeView unless I call. I've included this in my TreeView XAML to call a routine when the TreeViewItem is expanded: TreeViewItem.Expanded="TVExp" Most times opening the app we won't need to view those child items so I'm not filling them in when the app opens, rather each folder-like item has a place-holder item to indicate there ARE child items. The TreeView includes folder-like elements that will have child items. I have a TreeView bound to an ObservableCollection with a ViewModel. ![]()
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