在WPF中,如何从包含ListBox的DataTemplate内部数据绑定到Window DataContext？

Question

我有一个WPF窗口,其视图模型设置为其DataContext,并且具有一个带有DataTemplate的ListBox,其ItemsSource绑定到视图模型,如下例所示:

查看型号:

using System.Collections.Generic;

namespace Example
{
    class Member
    {
        public string Name { get; set; }
        public int Age { get; set; }
    }

    class Team
    {
        private List<Member> members = new List<Member>();

        public string TeamName { get; set; }
        public List<Member> Members { get { return members; } }
    }
}

MainWindow.xaml:

<Window x:Class="Example.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 xmlns:l="clr-namespace:Example" 
    Title="Example" Height="300" Width="300" Name="Main">

 <Window.DataContext>
  <l:Team TeamName="The best team">
   <l:Team.Members>
    <l:Member Name="John Doe" Age="23"/>
    <l:Member Name="Jane Smith" Age="20"/>
    <l:Member Name="Max Steel" Age="24"/>
   </l:Team.Members>
  </l:Team>
 </Window.DataContext>

 <ListBox ItemsSource="{Binding Path=Members}">
  <ListBox.ItemTemplate>
   <DataTemplate>
    <StackPanel Orientation="Horizontal">
     <TextBlock Text="{Binding Path=TeamName}" Margin="4"/>
     <TextBlock Text="{Binding Path=Name}" Margin="4"/>
    </StackPanel>
   </DataTemplate>
  </ListBox.ItemTemplate>
 </ListBox>
</Window>

当然,Team类的TeamName属性不会显示在ListBox项中,因为LisBox的每个项都是List.ItemTemplate的DataContext,它会覆盖Window的DataContext.

问题是:如何从ListBox的DataTemplate中数据绑定到视图模型(Window.DataContext)的TeamName属性？

Answer 1

你也可以使用RelativeSource绑定,它并不复杂:

<TextBlock Text="{Binding Path=DataContext.TeamName, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}" Margin="4"/>

Answer 2

我将l:Team声明提取到Window.Resources部分,并从DataContext和DataTemplate中引用它:

<Window x:Class="Example.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 xmlns:l="clr-namespace:Example" 
    Title="Example" Height="300" Width="300" Name="Main">

 <Window.Resources>
  <l:Team x:Key="data" TeamName="The best team">
   <l:Team.Members>
    <l:Member Name="John Doe" Age="23"/>
    <l:Member Name="Jane Smith" Age="20"/>
    <l:Member Name="Max Steel" Age="24"/>
   </l:Team.Members>
  </l:Team>
 <Window.Resources>

 <Window.DataContext>
     <StaticResource ResourceKey="data"/>
 </Window.DataContext>

 <ListBox ItemsSource="{Binding Path=Members}">
  <ListBox.ItemTemplate>
   <DataTemplate>
    <StackPanel Orientation="Horizontal">
     <TextBlock Text="{Binding Source={StaticResource data}, Path=TeamName}" Margin="4"/>
     <TextBlock Text="{Binding Path=Name}" Margin="4"/>
    </StackPanel>
   </DataTemplate>
  </ListBox.ItemTemplate>
 </ListBox>
</Window>