c# - WPF绑定RelativeSource

Question

只是在这里做一个小测试。只有这两个文本框中的第一个显示值“123”。第二个怎么没有？

<Window x:Class="Test.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:diag="clr-namespace:System.Diagnostics;assembly=WindowsBase"
    Title="MainWindow" Height="350" Width="525">
<StackPanel Width="123" x:Name="Panel1">
    <TextBox Text="{Binding ElementName=Panel1, Path=Width, diag:PresentationTraceSources.TraceLevel=High}"></TextBox>
    <TextBox Text="{Binding Source={RelativeSource AncestorType={x:Type StackPanel}}, Path=Width, diag:PresentationTraceSources.TraceLevel=High}"></TextBox>
</StackPanel>

Answer 1

而不是Sourcetake RelativeSource，像这样：

<TextBox Text="{Binding RelativeSource={RelativeSource AncestorType={x:Type StackPanel}}, Path=Width, diag:PresentationTraceSources.TraceLevel=High}"></TextBox>