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;
}