WPF在ItemsControl的ToolTip中显示来自多个DataContexts的数据

问题描述

我正在尝试显示一个 ItemsControl 生成的项目的工具提示，需要从概念上不相关的来源提取数据。例如，假设我有一个Item类，如下所示：

I am trying to display a tooltip for an item generated by an ItemsControl that needs to pull data from conceptually unrelated sources. For example, say I have an Item class as follows:

public class Item
{
    public string ItemDescription { get; set; }
    public string ItemName { get; set; }
}

我可以使用工具提示在ItemsControl中显示Item，如下所示： / p>

I can display the Item within an ItemsControl with a tooltip as follows:

<ItemsControl x:Name="itemsControl" ItemsSource="{Binding Items}">
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding ItemName}">
                <TextBlock.ToolTip>
                    <ToolTip>
                        <TextBlock Text="{Binding ItemDescription}" />
                    </ToolTip>
                </TextBlock.ToolTip>
            </TextBlock>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

但是说我有另一个可以通过 DataContext ItemsControl 。在工具提示中有没有办法做到这一点？例如

But say I have another property that can be accessed via the DataContext of the ItemsControl. Is there any way to do this from within the tooltip? E.g.,

<ItemsControl x:Name="itemsControl" ItemsSource="{Binding Items}">
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding ItemName}">
                <TextBlock.ToolTip>
                    <ToolTip>
                        <Grid>
                            <Grid.RowDefinitions>
                                <RowDefinition />
                                <RowDefinition />
                            </Grid.RowDefinitions>
                            <TextBlock Text="{Binding ItemDescription}" />
                            <TextBlock Grid.Row="1" Text="{Bind this to another property of the ItemsControl DataContext}" />
                        </Grid>
                    </ToolTip>
                </TextBlock.ToolTip>
            </TextBlock>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

我使用的测试窗口的代码如下：

The code for the test Window I used is as follows:

public partial class Window1 : Window
{
    public Window1()
    {
        InitializeComponent();

        List<Item> itemList = new List<Item>() {
            new Item() { ItemName = "First Item", ItemDescription = "This is the first item." },
            new Item() { ItemName = "Second Item", ItemDescription = "This is the second item." }
        };

        this.Items = itemList;
        this.GlobalText = "Something else for the tooltip.";
        this.DataContext = this;
    }

    public string GlobalText { get; private set; }

    public List<Item> Items { get; private set; }
}

所以在这个例子中，我想显示 GlobalText 属性（实际上这将是另一个自定义对象）。

So in this example I want to show the value of the GlobalText property (in reality this would be another custom object).

为了使事情变得复杂，我实际上使用DataTemplates并显示两个ItemsControl中的不同类型的对象，但任何帮助将不胜感激！

To complicate matters, I am actually using DataTemplates and show two different types of objects within the ItemsControl, but any assistance would be greatly appreciated!

推荐答案

经过一个小时的发拉我来以确信您不能在DataTemplate 中为ToolTip 引用另一个DataContext。对于其他绑定，其他海报已被证明是完全可能的。这就是为什么你不能使用RelativeSource的技巧。您可以做的是在Item类上实现静态属性，并引用 ：

After an hour of hair pulling I have come to the conviction that you can't reference another DataContext inside a DataTemplate for a ToolTip. For other Bindings it is perfectly possible as other posters have proven. That's why you can't use the RelativeSource trick either. What you can do is implement a static property on your Item class and reference that:

<Window x:Class="ToolTipSpike.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300"
    Name="Root"
    xmlns:ToolTipSpike="clr-namespace:ToolTipSpike">
    <Grid>
        <ItemsControl x:Name="itemsControl" ItemsSource="{Binding Items}">
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding ItemName}">
                        <TextBlock.ToolTip>
                            <ToolTip>
                                <Grid>
                                    <Grid.RowDefinitions>
                                        <RowDefinition />
                                        <RowDefinition />
                                    </Grid.RowDefinitions>
                                    <TextBlock Text="{Binding ItemDescription}" />
                                    <TextBlock Grid.Row="1"
                   Text="{Binding Source={x:Static ToolTipSpike:Item.GlobalText},
                   Path=.}"
                                    />
                                </Grid>
                            </ToolTip>
                        </TextBlock.ToolTip>
                    </TextBlock>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>
    </Grid>
</Window>

using System.Collections.Generic;
using System.Windows;

namespace ToolTipSpike
{
    public partial class Window1 : Window
    {

        public List<Item> Items { get; private set; }
        public Window1()
        {
            InitializeComponent();
            var itemList = new List<Item>
                  {
                      new Item { ItemName = "First Item", ItemDescription = "This is the first item." },
                      new Item { ItemName = "Second Item", ItemDescription = "This is the second item." }
                  };
            this.Items = itemList;
            this.DataContext = this;
       }
    }

     public class Item
     {
         static Item()
         {
             GlobalText = "Additional Text";
         }
         public static string GlobalText { get; set; }
         public string ItemName{ get; set;}
         public string ItemDescription{ get; set;}
     }
}

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