我有一个创建对象列表的简单类:
namespace TestWPF2
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public ObservableCollection<TestObj> SomeList { get; set; }
public string WindowTitle { get; set; }
public MainWindow()
{
this.DataContext = this;
WindowTitle = "People";
SomeList = new ObservableCollection<TestObj>();
SomeList.Add(new TestObj("Bob"));
SomeList.Add(new TestObj("Jane"));
SomeList.Add(new TestObj("Mike"));
InitializeComponent();
}
}
}
TestObj类如下:
namespace TestWPF2
{
public class TestObj
{
public string FirstName { get; set; }
public TestObj(string firstName)
{
this.FirstName = firstName;
}
}
}
然后我尝试使用以下内容显示列表中的每个项目:
<Window x:Class="TestWPF2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:TestWPF2"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<DataTemplate DataType="{x:Type local:TestObj}">
<StackPanel Orientation="Vertical">
<StackPanel Orientation="Horizontal">
<TextBlock Text="Pos: "/>
<TextBlock x:Name="posText"/>
</StackPanel>
<StackPanel Orientation="Horizontal">
<TextBlock Text="Name: "/>
<TextBlock Text="{Binding FirstName}"/>
</StackPanel>
</StackPanel>
<!-- THESE TRIGGERS DONT WORK -->
<DataTemplate.Triggers>
<Trigger Property="ItemsControl.AlternationIndex" Value="0">
<Setter Property="Text" Value="First" TargetName="posText"/>
</Trigger>
<Trigger Property="ItemsControl.AlternationIndex" Value="1">
<Setter Property="Text" Value="Second" TargetName="posText"/>
</Trigger>
<Trigger Property="ItemsControl.AlternationIndex" Value="3">
<Setter Property="Text" Value="Third" TargetName="posText"/>
</Trigger>
</DataTemplate.Triggers>
</DataTemplate>
</Window.Resources>
<StackPanel>
<TextBlock Text="{Binding Title}"/>
<ItemsControl HorizontalAlignment="Stretch"
ItemsSource="{Binding SomeList}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Vertical" />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
</StackPanel>
</Window>
我想要展示的是:
Pos: First
Name: Bob
Pos: Second
Name: Jane
etc.
绑定到列表中每个项的FirstName属性非常简单,但我还想绑定到列表中的 index 。我知道我可以使用ItemsControl.AlternationIndex在ItemsControl中执行此操作,但是如何从DataTemplate中的内部链接到AlternationIndex?
答案 0 :(得分:0)
您需要了解您的上下文是TestObj
,并且使用触发器,您基本上会检查名为ItemsControl
的属性的值,该属性应具有属性AlternationIndex
。
您应该使用RelativeSource绑定将触发器的上下文更改为保存对象的控件,名为ContentPresenter
:
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContentPresenter}}, Path=(ItemsControl.AlternationIndex)" Value="0">
<Setter Property="Text" Value="First" TargetName="posText"/>
</Trigger>
<!--- here be the other triggers -->
</DataTemplate.Triggers>
希望这会有所帮助..