Good morning. I have a class with data derived from InotifyPropertyChange. The data come from a background thread, which searches for files with certain extension in certain locations. Public property of the class reacts to an event OnPropertyChange by updating data in a separate thread. Besides, there are described in XAML TreeView, based on HierarhicalDataTemplates. Each TextBlock inside templates supplied ItemsSource = "{Binding FoundFilePaths, Mode = OneWay, NotifyOnTargetUpdated = True}".
<TreeView x:Name="FoundFiles_TreeView" Opacity="15" Background="White" BorderThickness="5" FontFamily="Arial" Margin="0,0,0,0" RenderTransformOrigin="0.5,0.5" VerticalAlignment="Top" Height="360" FontWeight="Bold" Foreground="#FF539DBE" TargetUpdated="FoundFiles_TreeView_TargetUpdated">
<TreeView.ItemContainerStyle >
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="TreeViewItem.Tag" Value="InfoNode" />
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
<Setter Property="Foreground" Value="Brown"/>
<Style.Triggers>
<Trigger Property="IsMouseCaptured" Value="True">
<Setter Property="IsSelected" Value="True"/>
</Trigger>
</Style.Triggers>
</Style>
</TreeView.ItemContainerStyle>
<TreeView.Resources>
<HierarchicalDataTemplate DataType = "{x:Type lightvedo:FilesInfoStore}" ItemsSource="{Binding FoundFilePaths, Mode=OneWay, NotifyOnTargetUpdated=True}">
<!--Здесь указываются узлы дерева-->
<StackPanel x:Name ="TreeNodeStackPanel" Orientation="Horizontal">
<TextBlock Margin="5,5,5,5" TargetUpdated="TextBlockExtensions_TargetUpdated">
<TextBlock.Text>
<MultiBinding StringFormat="Files with Extension {0}">
<Binding Path="FileExtension"/>
</MultiBinding>
</TextBlock.Text>
</TextBlock>
<Button x:Name="OpenFolderForThisFiles" Click="OnOpenFolderForThisFiles_Click" Margin="5, 3, 5, 3" Width="22" Background="Transparent" BorderBrush="Transparent" BorderThickness="0.5">
<Image Source="images\Folder.png" Height="16" Width="20" >
</Image>
</Button>
</StackPanel>
</HierarchicalDataTemplate>
<HierarchicalDataTemplate DataType="{x:Type lightvedo:FilePathsStore}">
<TextBlock Text="{Binding FilePaths, Mode=OneWay, NotifyOnTargetUpdated=True}" TargetUpdated="OnTreeViewNodeChildren_Update" />
</HierarchicalDataTemplate>
</TreeView.Resources>
<TreeView.RenderTransform>
<TransformGroup>
<ScaleTransform/>
<SkewTransform AngleX="-0.083"/>
<RotateTransform/>
<TranslateTransform X="-0.249"/>
</TransformGroup>
</TreeView.RenderTransform>
<TreeView.BorderBrush>
<LinearGradientBrush EndPoint="1,0.5" StartPoint="0,0.5">
<GradientStop Color="#FF74591F" Offset="0" />
<GradientStop Color="#FF9F7721" Offset="1" />
<GradientStop Color="#FFD9B972" Offset="0.49" />
</LinearGradientBrush>
</TreeView.BorderBrush>
</TreeView>
Q: Why is the data from a class derived from INotifyPropertyChange does not affect the display of tree items. Do I understand: The interface will make INotifyPropertyChange be automatically redrawn TreeViewItems or do I need to manually carry out this operation? Currently TreeViewItems not updated and PropertyChamged always null. A feeling that no subscribers to the event OnPropertyChanged.
You don't need to set the NotifyOnTargetUpdated.
Instead, make sure to raise the PropertyChanged event (with the appropriate property-name passed with the PropertyChangedEventArgs passed to the handler) on the parent entity each time the paths collection is updated, or have the navigation property be an implementation of INotifyCollectionChanged.