您应该绑定到ActualHeight，它指定了它的排列高度。 Height 属性允许您设置一个固定的高度，但并不能准确地告诉您排列后的高度。
编辑：
实际上，这是一个带有 Silverlight 的known bug。
您必须像这样使用 SizeChanged 事件：
<UserControl x:Class="SilverlightApplication3.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400">
<Grid x:Name="LayoutRoot" Background="White">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Button Content="Add Item" Click="Button_Click" />
<ListBox x:Name="listBox1" Grid.Column="0" Grid.Row="1" VerticalAlignment="Top" SizeChanged="listBox1_SizeChanged" />
<ListBox x:Name="listBox2" Grid.Column="1" Grid.Row="1" VerticalAlignment="Top" />
</Grid>
</UserControl>
带有代码隐藏：
using System.Windows;
using System.Windows.Controls;
namespace SilverlightApplication3 {
public partial class MainPage : UserControl {
public MainPage() {
InitializeComponent();
}
private int counter;
private void Button_Click(object sender, RoutedEventArgs e) {
this.counter++;
this.listBox1.Items.Add(counter.ToString());
}
private void listBox1_SizeChanged(object sender, SizeChangedEventArgs e) {
this.listBox2.Height = this.listBox1.ActualHeight;
}
}
}
你也可以把它包装成一个很好的附加行为。
编辑：
这是这样的行为：
<UserControl x:Class="SilverlightApplication3.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:SilverlightApplication3"
mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400">
<Grid x:Name="LayoutRoot" Background="White">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Button Content="Add Item" Click="Button_Click" />
<ListBox x:Name="listBox1" Grid.Column="0" Grid.Row="1" VerticalAlignment="Top" />
<ListBox x:Name="listBox2" Grid.Column="1" Grid.Row="1" VerticalAlignment="Top" local:SizeSynchronizationBehavior.HeightElement="{Binding ElementName=listBox1}" />
</Grid>
</UserControl>
带有代码隐藏：
using System;
using System.Windows;
using System.Windows.Controls;
namespace SilverlightApplication3 {
public partial class MainPage : UserControl {
public MainPage() {
InitializeComponent();
}
private int counter;
private void Button_Click(object sender, RoutedEventArgs e) {
this.counter++;
this.listBox1.Items.Add(counter.ToString());
}
}
public static class SizeSynchronizationBehavior {
#region Dependency Properties
///////////////////////////////////////////////////////////////////////////////////
// HeightElement
///////////////////////////////////////////////////////////////////////////////////
/// <summary>
/// Identifies the <c>HeightElement</c> attached dependency property. This field is read-only.
/// </summary>
/// <value>The identifier for the <c>HeightElement</c> attached dependency property.</value>
public static readonly DependencyProperty HeightElementProperty = DependencyProperty.RegisterAttached("HeightElement",
typeof(FrameworkElement), typeof(SizeSynchronizationBehavior), new PropertyMetadata(null, OnHeightElementPropertyValueChanged));
/// <summary>
/// Gets the value of the <see cref="HeightElementProperty"/> attached property for the specified <see cref="FrameworkElement"/>.
/// </summary>
/// <param name="obj">The object to which the attached property is retrieved.</param>
/// <returns>
/// The value of the <see cref="HeightElementProperty"/> attached property for the the specified <see cref="FrameworkElement"/>.
/// </returns>
public static FrameworkElement GetHeightElement(FrameworkElement obj) {
if (obj == null) throw new ArgumentNullException("obj");
return (FrameworkElement)obj.GetValue(HeightElementProperty);
}
/// <summary>
/// Sets the value of the <see cref="HeightElementProperty"/> attached property to the specified <see cref="FrameworkElement"/>.
/// </summary>
/// <param name="obj">The object to which the attached property is written.</param>
/// <param name="value">
/// The new value of the <see cref="HeightElementProperty"/> attached property to the specified <see cref="FrameworkElement"/>.
/// </param>
public static void SetHeightElement(FrameworkElement obj, FrameworkElement value) {
if (obj == null) throw new ArgumentNullException("obj");
obj.SetValue(HeightElementProperty, value);
}
/// <summary>
/// Called when <see cref="HeightElementProperty"/> is changed.
/// </summary>
/// <param name="d">The dependency object that was changed.</param>
/// <param name="e">The <see cref="DependencyPropertyChangedEventArgs"/> instance containing the event data.</param>
private static void OnHeightElementPropertyValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
FrameworkElement element = d as FrameworkElement;
if (element == null)
return;
SizeChangedEventHandler heightSizeChangedEventHandler = GetSizeChangedEventHandler(element);
if (heightSizeChangedEventHandler == null) {
heightSizeChangedEventHandler = (sender, eventArgs) => {
FrameworkElement he = GetHeightElement(element);
if (he != null)
element.Height = he.ActualHeight;
};
SetSizeChangedEventHandler(element, heightSizeChangedEventHandler);
}
FrameworkElement heightElement = e.OldValue as FrameworkElement;
if (heightElement != null)
heightElement.SizeChanged += heightSizeChangedEventHandler;
heightElement = e.NewValue as FrameworkElement;
if (heightElement != null)
heightElement.SizeChanged += heightSizeChangedEventHandler;
}
///////////////////////////////////////////////////////////////////////////////////
// SizeChangedEventHandler
///////////////////////////////////////////////////////////////////////////////////
/// <summary>
/// Identifies the <c>SizeChangedEventHandler</c> attached dependency property. This field is read-only.
/// </summary>
/// <value>The identifier for the <c>SizeChangedEventHandler</c> attached dependency property.</value>
private static readonly DependencyProperty SizeChangedEventHandlerProperty = DependencyProperty.RegisterAttached("SizeChangedEventHandler",
typeof(SizeChangedEventHandler), typeof(SizeSynchronizationBehavior), new PropertyMetadata(null));
/// <summary>
/// Gets the value of the <see cref="SizeChangedEventHandlerProperty"/> attached property for the specified <see cref="FrameworkElement"/>.
/// </summary>
/// <param name="obj">The object to which the attached property is retrieved.</param>
/// <returns>
/// The value of the <see cref="SizeChangedEventHandlerProperty"/> attached property for the the specified <see cref="FrameworkElement"/>.
/// </returns>
private static SizeChangedEventHandler GetSizeChangedEventHandler(FrameworkElement obj) {
if (obj == null) throw new ArgumentNullException("obj");
return (SizeChangedEventHandler)obj.GetValue(SizeChangedEventHandlerProperty);
}
/// <summary>
/// Sets the value of the <see cref="SizeChangedEventHandlerProperty"/> attached property to the specified <see cref="FrameworkElement"/>.
/// </summary>
/// <param name="obj">The object to which the attached property is written.</param>
/// <param name="value">
/// The new value of the <see cref="SizeChangedEventHandlerProperty"/> attached property to the specified <see cref="FrameworkElement"/>.
/// </param>
private static void SetSizeChangedEventHandler(FrameworkElement obj, SizeChangedEventHandler value) {
if (obj == null) throw new ArgumentNullException("obj");
obj.SetValue(SizeChangedEventHandlerProperty, value);
}
#endregion // Dependency Properties
}
}