獲取ItemsSource的DataTemplate對象

Question

我有一個看起來像這樣的TabControl：

<TabControl x:Name="TabControl" SelectedIndex="0" ItemsSource="{Binding Diagrams}" SelectionChanged="TabControl_OnSelectionChanged">
        <TabControl.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="Test">
                </TextBlock>
            </DataTemplate>
        </TabControl.ItemTemplate>
        <TabControl.ContentTemplate>
            <DataTemplate>
                <drawingBoard:DrawingBoard x:Name="TheDrawingBoard" DockPanel.Dock="Top" Focusable="True"/>
            </DataTemplate>
        </TabControl.ContentTemplate>
    </TabControl>

我之前擴展的代碼無法創建動態選項卡，並且需要DrawingBoard的對象來做一些事情。 由於我使用ItemsSource，因此我在SelectionChanged事件中僅獲得一個Diagrams對象。 如何獲取當前所選選項卡的ContentTemplate.DataTemplate對象（DrawingBoard）？

Answer 1

您必須遍歷VisualTree。 此類型只有一個子元素，即來自當前選項卡。

private void TabControl_OnSelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if ((sender as TabControl)!=null)
            {
                var yourCtl = GetChildren<DrawingBoard>((sender as TabControl)).FirstOrDefault() as DrawingBoard;
            }
        }

        IEnumerable<T> GetChildren<T>(FrameworkElement parent) where T : FrameworkElement
        {
            var chCount = VisualTreeHelper.GetChildrenCount(parent);
            for (int i = 0; i < chCount; i++)
            {
                var child = VisualTreeHelper.GetChild(parent, i);
                if (child is T)
                {   
                    yield return child as T;
                }
                if (child is FrameworkElement)
                {
                    foreach (var item in GetChildren<T>(child as FrameworkElement))
                    {
                        yield return item;
                    };
                }
            }
        }

Answer 2

找到了解決我問題的方法。 解決方案由WPF博士解決。

private void TabControl_OnLoaded(object sender, RoutedEventArgs e)
    {
        TabControl tabControl = sender as TabControl;
        ContentPresenter cp =
            tabControl.Template.FindName("PART_SelectedContentHost", tabControl) as ContentPresenter;

        var db = tabControl.ContentTemplate.FindName("TheDrawingBoard", cp) as DrawingBoard;
        CurrentlySelectedDrawingBoard = db;
    }