WPF Multilevel TreeView Expanding Issue

Question

I have a multilevel TreeView upto 4 levels as below :

 <HierarchicalDataTemplate ItemsSource="{Binding TestModuleStatementList}" x:Key="level4" ItemTemplate="{StaticResource level5}">
                <Grid>
                    <Grid.ColumnDefinitions>

                        <ColumnDefinition Width="600"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                    </Grid.ColumnDefinitions>
                    <TextBlock Grid.Column="0" Margin="1,1,0,1" Name="lblStatementName" Style="{StaticResource TreeLabelStyle}" MouseLeftButtonUp="ViewTestDataTree_MouseLeftButtonUp" MouseRightButtonUp="ViewTestDataTree_MouseRightButtonUp" Padding="2,2,2,2" Text="{Binding DisplayText}" />
                    <Border Grid.Column="1" Margin="0,0,-2,0" Style="{StaticResource BorderStylePassCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockPassCountStyleTestData}"/>
                    </Border>

                    <Border Grid.Column="2" Margin="0,0,-2,0" Style="{StaticResource BorderStyleFailCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockFailCountStyleTestData}"/>
                    </Border>
                    <Border Grid.Column="3" Margin="0,0,-2,0" Style="{StaticResource BorderStyleModulePassCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockModulePassCountStyleTestData}"/>
                    </Border>
                    <Border Grid.Column="4" Margin="0,0,-2,0" Style="{StaticResource BorderStyleModuleFailCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockModuleFailCountStyleTestData}"/>
                    </Border>
                </Grid>
            </HierarchicalDataTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding TestModules}" x:Key="level3" ItemTemplate="{StaticResource level4}">
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="620"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                    </Grid.ColumnDefinitions>
                    <TextBlock Grid.Column="0" Margin="1,1,0,1" Name="lblCategoryName" Style="{StaticResource TreeLabelStyle}" MouseLeftButtonUp="ViewTestDataTree_MouseLeftButtonUp" MouseRightButtonUp="ViewTestDataTree_MouseRightButtonUp" Padding="2,2,2,2" Text="{Binding DisplayText}" />
                    <Border Grid.Column="1" Margin="0,0,-2,0" Style="{StaticResource BorderStylePassCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockPassCountStyleTestData}"/>
                    </Border>
                    <Border Grid.Column="2" Margin="0,0,-2,0" Style="{StaticResource BorderStyleFailCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockFailCountStyleTestData}"/>
                    </Border>
                    <Border Grid.Column="3" Margin="0,0,-2,0" Style="{StaticResource BorderStyleModulePassCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockModulePassCountStyleTestData}"/>
                    </Border>
                    <Border Grid.Column="4" Margin="0,0,-2,0" Style="{StaticResource BorderStyleModuleFailCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockModuleFailCountStyleTestData}"/>
                    </Border>
                </Grid>
            </HierarchicalDataTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding TestModuleCategories}" x:Key="level2" ItemTemplate="{StaticResource level3}">
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="640"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                    </Grid.ColumnDefinitions>

                    <TextBlock Grid.Column="0" Margin="1,1,1,1" Name="lblDeviceName" MouseLeftButtonUp="ViewTestDataTree_MouseLeftButtonUp" MouseRightButtonUp="ViewTestDataTree_MouseRightButtonUp" ToolTip="{Binding DisplayText}" Style="{StaticResource TreeLabelStyle}" Padding="2,2,2,2" Text="{Binding DisplayText}" />
                    <TextBox Grid.Column="0" Margin="1,1,1,1" Name="DeviceNameTextBox" LostFocus="TextBox_LostFocus" 
                                             Text="{Binding RenameDeviceText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" 
                                             PreviewKeyDown="TextBox_PreviewKeyDown"
                                             Padding="2,2,2,2" MaxLength="100" 
                                            Visibility="{Binding Path=Edit, Converter={StaticResource BoolToVisibilityCollapsedConverter}, UpdateSourceTrigger=PropertyChanged,Mode=TwoWay}">
                        <TextBox.CommandBindings>
                            <CommandBinding Command="Paste" CanExecute="CommandBinding_CanExecute"/>
                        </TextBox.CommandBindings>
                    </TextBox>
                    <Border Grid.Column="1" Margin="0,0,-1,0" Style="{StaticResource BorderStylePassCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockPassCountStyleTestData}"/>
                    </Border>
                    <Border Grid.Column="2" Margin="0,0,-1,0" Style="{StaticResource BorderStyleFailCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockFailCountStyleTestData}"/>
                    </Border>
                    <Border Grid.Column="3" Margin="0,0,-1,0" Style="{StaticResource BorderStyleModulePassCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockModulePassCountStyleTestData}"/>
                    </Border>
                    <Border Grid.Column="4" Margin="0,0,-1,0" Style="{StaticResource BorderStyleModuleFailCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockModuleFailCountStyleTestData}"/>
                    </Border>
                </Grid>
            </HierarchicalDataTemplate>

<HierarchicalDataTemplate ItemsSource="{Binding TestRuns}" x:Key="level1" ItemTemplate="{StaticResource level2}" >
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="660"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                        <ColumnDefinition Width="130"/>
                    </Grid.ColumnDefinitions>
                    <TextBlock Grid.Column="0" Margin="1,1,2,1" Name="lblProjectName" MouseLeftButtonUp="ViewTestDataTree_MouseLeftButtonUp" MouseRightButtonUp="ViewTestDataTree_MouseRightButtonUp" Style="{StaticResource TreeLabelStyle}" Padding="2,2,2,2" Text="{Binding DisplayText}"/>
                    <Border Grid.Column="1" Style="{StaticResource BorderStylePassCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockPassCountStyleTestData}"/>
                    </Border>
                    <Border Grid.Column="2" Style="{StaticResource BorderStyleFailCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockFailCountStyleTestData}"/>
                    </Border>
                    <Border Grid.Column="3" Style="{StaticResource BorderStyleModulePassCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockModulePassCountStyleTestData}"/>
                    </Border>
                    <Border Grid.Column="4" Style="{StaticResource BorderStyleModuleFailCountTestData}">
                        <TextBlock Style="{StaticResource TextBlockModuleFailCountStyleTestData}"/>
                    </Border>
                </Grid>
            </HierarchicalDataTemplate>



<TreeView BorderThickness="0" Name="ViewTestDataTree" VirtualizingStackPanel.IsVirtualizing = "True"
                              VirtualizingStackPanel.VirtualizationMode = "Recycling" ItemsSource="{Binding Projects}" Grid.Row="1" 
                              ItemTemplate="{StaticResource level1}"  Background="{StaticResource ATAM_WindowBackground}" FocusVisualStyle="{x:Null}">
                        <TreeView.ItemContainerStyle>
                            <!-- Make the focus highlight rectangle, around the current tree item, barely visible -->
                            <Style TargetType="{x:Type TreeViewItem}">
                                <Style.Resources>
                                    <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="#FF202020" />
                                    <SolidColorBrush x:Key="{x:Static SystemColors.InactiveSelectionHighlightBrushKey}" Color="#FF202020" />
                                </Style.Resources>
                                <Setter Property="IsExpanded" Value="{Binding IsExpanded}"/>
                                <EventSetter Event="TreeViewItem.Expanded" Handler="TreeViewItem_Expanded"/>
                                <EventSetter Event="TreeViewItem.Collapsed" Handler="TreeViewItem_Collapsed"/>
                            </Style>
                        </TreeView.ItemContainerStyle>
                    </TreeView>

Here I had a setter in TreeView.ItemContainerStyle that Setter Property="IsExpanded" Value="{Binding IsExpanded}" but when i set TestStamentList which is level 4 IsExpanded property to True from code then that item is not getting expanded. I want to Expand children with some specific condition on a Button Click(Find Next Button) event.

Note:-I have IsExpanded property on all list levels(4 levels) and i am setting IsExpanded=true of last level list(TestModuleStatementList).

Below is my Button Click Event:

 private void FindNextFailButton_Click(object sender, RoutedEventArgs e)
        {
                foreach (var Project in Projects)
                {
                    foreach (var Devices in Project.TestRuns)
                    {
                        foreach (var Category in Devices.TestModuleCategories)
                        {
                            foreach (var TestModule in Category.TestModules)
                            {
                                foreach (var statement in TestModule.TestModuleStatementList)
                                {
                                    if(statement.ModuleFailed==1)
                                    {
                                        //TreeViewItem item = ViewTestDataTree.ItemContainerGenerator.ContainerFromItem(statement) as TreeViewItem;
                                        //item.IsExpanded = true;
                                        Project.IsExpanded = true;
                                        Devices.IsExpanded = true;
                                        Category.IsExpanded = true;
                                        TestModule.IsExpanded = true;
                                        statement.IsExpanded = true;
                                        statement.IsSelected = true;
                                        return;
                                        //ViewTestDataTree.SelectedItem = statement;
                                    }
                                }

                            }
                        }
                    }
                }
            }
        }

Kindly provide some help

Thanks In Advance.

Answer 1

I am posting this as answer because i cannot mark solved in comment. https://docs.microsoft.com/en-us/dotnet/framework/wpf/controls/how-to-find-a-treeviewitem-in-a-treeview