WPF---数据绑定之RelativeSource

Posted 2021-01-11 3xiaolonglong

一、概述

当Binding有明确的数据来源的时候，我们可以用Source或者ElementName赋值的办法让Binding与之关联。

但是，有时候当我们不能确定作为Source的对象叫什么名字的时候，但我们知道它与作为Binding目标的对象在UI布局上的对应关系的时候，我们就

需要使用Binding的RelativeSource属性了。

二、例子

以下例子演示了使用Binding的RelativeSource属性来绑定父级容器的Name属性以及控件本身的Name属性。

 1 <Window x:Class="BindingDemo3XmlDataSource.MainWindow"
 2         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 3         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 4         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
 5         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
 6         xmlns:local="clr-namespace:BindingDemo3XmlDataSource"
 7         mc:Ignorable="d"
 8         Title="BindingDemo3RelativeSource" Height="350" Width="525">
 9     <Grid x:Name="g1" Margin="10" Background="Red">
10         <DockPanel x:Name="d1" Margin="10" Background="Pink" >
11             <Grid x:Name="g2" Margin="20" Background="Green" >
12                 <DockPanel x:Name="d2" Margin="10" Background="PaleVioletRed" >
13                     <Grid x:Name="g3" Margin="10" Background="Red">
14                         <Grid x:Name="g4" Margin="10" Background="Green">
15                             <Grid.RowDefinitions>
16                                 <RowDefinition Height="*"/>
17                                 <RowDefinition Height="*"/>
18                                 <RowDefinition Height="*"/>
19                             </Grid.RowDefinitions>
20                             <TextBox Background="AliceBlue" 
21                                      Text="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorLevel=4,AncestorType={x:Type Grid}}, Path=Name}"
22                                      FontSize="22" FontWeight="Bold" TextAlignment="Center">
23                                      
24                                 
25                             </TextBox>
26                             <TextBox Grid.Row="1" Background="Silver"
27                                      Text="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorLevel=1,AncestorType={x:Type DockPanel}}, Path=Name}"
28                                      FontSize="22" FontWeight="Bold" TextAlignment="Center">
29                                 
30                             </TextBox>
31                             <TextBox Grid.Row="2" Background="AliceBlue" Name="TextBox1"
32                                      Text="{Binding RelativeSource={RelativeSource Mode=Self}, Path=Name}"
33                                      FontSize="22" FontWeight="Bold" TextAlignment="Center">
34 
35                             </TextBox>
36                         </Grid>
37                     </Grid>
38                 </DockPanel>
39             </Grid>
40         </DockPanel>
41     </Grid>
42 </Window>

View Code

部分等价的C#代码参考以下：

  　　   RelativeSource rs = new RelativeSource();
            rs.Mode = RelativeSourceMode.Self;
            Binding binding = new Binding("Name") {RelativeSource = rs };
            this.TextBox1.SetBinding(TextBox.TextProperty, binding);

结果如下：