WPF - DataTemplate 하위 요소 Style 적용

ListView Item의 DataTemplate의 TextBlock 및 Rectangle의 색을 코드로 직접 정하고 싶었음

  <ListView ItemsSource="{Binding FileInfos}" 
                  SelectedItem="{Binding SelectedFileInfo}"
                  Style="{DynamicResource FileLoadListViewStyle}"
                  ItemContainerStyle="{StaticResource FileItemStyle}"
                  x:Name="xFileInfoListView">
            <ListView.ItemsPanel>
                <ItemsPanelTemplate >
                    <WrapPanel/>
                </ItemsPanelTemplate>
            </ListView.ItemsPanel>

            <ListView.ItemTemplate>
                <DataTemplate>
                    <DockPanel Loaded="FrameworkElement_OnLoaded">
                        <TextBlock  x:Name="xTextBlockInDataTemplate" DockPanel.Dock="Bottom" Text="{Binding Name}" Style="{DynamicResource FileViewerListItemTextBlockStyle}"  />
                        <Rectangle x:Name="xRectangleInDataTemplate" Style="{DynamicResource FileViewerRectangleStyle}">
                            <Rectangle.OpacityMask>
                                <VisualBrush Stretch="Fill" Visual="{DynamicResource BinaryFile}"/>
                            </Rectangle.OpacityMask>
                        </Rectangle>
                    </DockPanel>
                </DataTemplate>
            </ListView.ItemTemplate>

        </ListView>

DataTemplate의 요소의 이름을 주어도 직접적으로 접근을 할 수 없음.

해결방법

VisualTreeHelper를 사용하여 해결

    private childItem FindVisualChild<childItem>(DependencyObject obj)
            where childItem : DependencyObject
        {
            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++)
            {
                DependencyObject child = VisualTreeHelper.GetChild(obj, i);
                if (child != null && child is childItem)
                {
                    return (childItem)child;
                }
                else
                {
                    childItem childOfChild = FindVisualChild<childItem>(child);
                    if (childOfChild != null)
                        return childOfChild;
                }
            }
            return null;
        }
        
        public void DataTemplateElementsColorChange(ColorBuffer buffer)
        {
            var xListView = _FileInfoComponentV.xFileInfoListView;
            foreach (var item in xListView.Items.SourceCollection)
            {
                System.Windows.Controls.ListViewItem myListViewItems =
                    (System.Windows.Controls.ListViewItem)(xListView.ItemContainerGenerator.ContainerFromItem(item));
                if (myListViewItems != null)
                {
                    ContentPresenter myContentPresenter = FindVisualChild<ContentPresenter>(myListViewItems);
                    DataTemplate myDataTemplate = myContentPresenter.ContentTemplate;
                    DataTemplate myDataTemplate2 = myListViewItems.ContentTemplate;
                    TextBlock myTextBlock = (TextBlock)myDataTemplate.FindName("xTextBlockInDataTemplate", myContentPresenter);
                    Rectangle myRectangle = (Rectangle)myDataTemplate.FindName("xRectangleInDataTemplate", myContentPresenter);

                    myTextBlock.Foreground =
                        new SolidColorBrush(buffer.TextForegroundColor);
                    myRectangle.Fill = new SolidColorBrush(buffer.TextForegroundColor);
                }
            }
        }

여기서 요소의 제일 안쪽에 있는 ContentPresenter에 접근하여 바꿀 수 있었다.

WPF 아주 어렵다.