寻找到DataTemplate中定义的元素

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转载最新推荐文章于 2022-12-26 13:17:05 发布 · 228 阅读

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原文链接：http://www.cnblogs.com/bear831204/archive/2008/10/17/1313432.html

本文介绍如何在WPF应用程序中通过DataTemplate找到特定元素的方法。利用ListBox的ItemContainerGenerator和FindName方法，结合FindVisualChild辅助函数实现对DataTemplate生成的TextBlock元素的查找。

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寻找到DataTemplate中定义的元素

例如DataTemplate如下：
<DataTemplate x:Key="myDataTemplate">
<TextBlock Name="textBlock" FontSize="14" Foreground="Blue">
    <TextBlock.Text>
      <Binding XPath="Title"/>
    </TextBlock.Text>
</TextBlock>
</DataTemplate>

在ListBoxItem中应用它：
<ListBox Name="myListBox" ItemTemplate="{StaticResource myDataTemplate}"
         IsSynchronizedWithCurrentItem="True">
<ListBox.ItemsSource>
    <Binding Source="{StaticResource InventoryData}" XPath="Books/Book"/>
</ListBox.ItemsSource>
</ListBox>
这里IsSynchronizedWithCurrentItem="True"保证SelectedItem就是CurrentItem。
如果要找到DataTemplate为具体的某一个ListBoxItem生成的TextBlock元素，就先要找到这个ListBoxItem里面的ContentPresenter，然后调用DataTemplate的FindName方法：
// Getting the currently selected ListBoxItem
// Note that the ListBox must have
// IsSynchronizedWithCurrentItem set to True for this to work
ListBoxItem myListBoxItem =
    (ListBoxItem)(myListBox.ItemContainerGenerator.ContainerFromItem(myListBox.Items.CurrentItem));

// Getting the ContentPresenter of myListBoxItem
ContentPresenter myContentPresenter = FindVisualChild<ContentPresenter>(myListBoxItem);

// Finding textBlock from the DataTemplate that is set on that ContentPresenter
DataTemplate myDataTemplate = myContentPresenter.ContentTemplate;
TextBlock myTextBlock = (TextBlock)myDataTemplate.FindName("textBlock", myContentPresenter);

// Do something to the DataTemplate-generated TextBlock
MessageBox.Show("The text of the TextBlock of the selected list item: "
    + myTextBlock.Text);

下面这个where型的写法用来寻找obj里面的一个类型为childItem的child，在本例中就是寻找myListBoxItem里面的一个类型为ContentPresenter的child。
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;
}

posted on 2008-10-17 13:34 cutebear 阅读( ...) 评论( ...) 编辑收藏

转载于:https://www.cnblogs.com/bear831204/archive/2008/10/17/1313432.html