DataContextChanged - FrameworkElement 的 DataContext 发生变化时触发的事件
UpdateSourceTrigger - 数据更新的触发方式
对绑定的数据做自定义转换
示例
1、演示 DataContextChanged 的用法
Bind/DataContextChanged.xaml
x:Class="Windows10.Bind.DataContextChanged"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Windows10.Bind"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Grid Background="Transparent">
<StackPanel Margin="10 0 10 10">
<TextBlock Name="lblMsg" Margin="5" />
<Button x:Name="btnChange" Content="改变 listBox 的数据上下文" Click="btnChange_Click" Margin="5" />
<ListBox x:Name="listBox" ItemsSource="{Binding}" DataContextChanged="listBox_DataContextChanged" Background="Orange" Margin="5" />
</StackPanel>
</Grid>
</Page>
Bind/DataContextChanged.xaml.cs
* DataContextChanged - FrameworkElement 的 DataContext 发生变化时触发的事件
using System;
using System.Collections.Generic;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
namespace Windows10.Bind
public sealed partial class DataContextChanged : Page
public DataContextChanged()
this.InitializeComponent();
this.Loaded += DataContextChanged_Loaded;
private void DataContextChanged_Loaded(object sender, RoutedEventArgs e)
// 指定数据上下文
listBox.DataContext = new List<string> { "a", "b", "c" };
private void btnChange_Click(object sender, RoutedEventArgs e)
// 修改数据上下文
listBox.DataContext = new List<string> { "a", "b", new Random().Next(0, 1000).ToString().PadLeft(3, '0') };
private void listBox_DataContextChanged(FrameworkElement sender, DataContextChangedEventArgs args)
* FrameworkElement.DataContextChanged - 数据上下文发生改变后触发的事件
// 数据上下文发生改变后
lblMsg.Text = "数据上下文发生改变：" + DateTime.Now.ToString("hh:mm:ss");
2、演示 UpdateSourceTrigger 的用法
Bind/UpdateSourceTrigger.xaml
x:Class="Windows10.Bind.UpdateSourceTrigger"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Windows10.Bind"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Grid Background="Transparent">
<StackPanel Margin="10 0 10 10">
<TextBlock Name="lblMsg" Foreground="Orange" Margin="5" />
UpdateSourceTrigger - 数据更新的触发方式
Default - 失去焦点后触发
PropertyChanged - 属性值发生改变后触发
Explicit - 需要通过 BindingExpression.UpdateSource() 显示触发
<TextBox Text="{Binding Text, Mode=TwoWay, ElementName=lblMsg, UpdateSourceTrigger=Default}" Margin="5" />
<TextBox Text="{Binding Text, Mode=TwoWay, ElementName=lblMsg, UpdateSourceTrigger=PropertyChanged}" Margin="5" />
<TextBox Name="txtExplicit" Text="{Binding Text, Mode=TwoWay, ElementName=lblMsg, UpdateSourceTrigger=Explicit}" Margin="5" />
<Button Name="btnBinding" Content="显示触发更新" Click="btnBinding_Click" Margin="5" />
</StackPanel>
</Grid>
</Page>
Bind/UpdateSourceTrigger.xaml.cs
* UpdateSourceTrigger - 数据更新的触发方式
* Default - 失去焦点后触发
* PropertyChanged - 属性值发生改变后触发
* Explicit - 需要通过 BindingExpression.UpdateSource() 显示触发
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Data;
namespace Windows10.Bind
public sealed partial class UpdateSourceTrigger : Page
public UpdateSourceTrigger()
this.InitializeComponent();
private void btnBinding_Click(object sender, RoutedEventArgs e)
// 显示触发 txtExplicit 的数据更新
BindingExpression be = txtExplicit.GetBindingExpression(TextBox.TextProperty);
be.UpdateSource();
3、演示如何对绑定的数据做自定义转换
Bind/BindingConverter.xaml
x:Class="Windows10.Bind.BindingConverter"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Windows10.Bind"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Grid Background="Transparent">
<StackPanel Margin="10 0 10 10">
配置 IValueConverter 资源
<StackPanel.Resources>
<local:IntegerLetterConverter x:Key="IntegerLetterConverter"/>
</StackPanel.Resources>
<Slider Name="slider1" Minimum="97" Maximum="122" Value="1" Width="300" Background="White" HorizontalAlignment="Left" Margin="5" />
演示如何使用 Binding 的 Converter, ConverterParameter, ConverterLanguage
注：ConverterParameter 和 ConverterLanguage 不支持绑定，只能配置为一个静态的值（但是在 C# 端可以实现一些在 xaml 中无法实现的特性，详见后面的例子）
<TextBox Name="textBox1" Width="300" HorizontalAlignment="Left" Margin="5"
Text="{Binding ElementName=slider1, Path=Value, Mode=TwoWay,
Converter={StaticResource IntegerLetterConverter},
ConverterParameter=param,
ConverterLanguage=zh}" />
<Slider Name="slider2" Minimum="97" Maximum="122" Value="1" Width="300" Background="White" HorizontalAlignment="Left" Margin="5" />
在 C# 端使用 Binding 的 Converter, ConverterParameter, ConverterLanguage
<TextBox Name="textBox2" Width="300" HorizontalAlignment="Left" Margin="5" />
<TextBlock Name="lblMsg" TextWrapping="Wrap" />
</StackPanel>
</Grid>
</Page>
Bind/BindingConverter.xaml.cs
* 演示如何对绑定的数据做自定义转换
using System;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Data;
namespace Windows10.Bind
public sealed partial class BindingConverter : Page
public BindingConverter()
this.InitializeComponent();
this.Loaded += BindingConverter_Loaded;
private void BindingConverter_Loaded(object sender, RoutedEventArgs e)
// 实例化 Binding 对象
Binding binding = new Binding()
ElementName = nameof(slider2),
Path = new PropertyPath(nameof(Slider.Value)),
Mode = BindingMode.TwoWay, // 默认是 OneWay 的
Converter = new IntegerLetterConverter(),
ConverterParameter = lblMsg, // 将 ConverterParameter 设置为一个指定的控件，这个在 xaml 中实现不了，但是可以在 C# 端实现
ConverterLanguage = "zh"
// 将目标对象的目标属性与指定的 Binding 对象关联
BindingOperations.SetBinding(textBox2, TextBox.TextProperty, binding);
// 自定义一个实现了 IValueConverter 接口的类，用于对绑定的数据做自定义转换
public sealed class IntegerLetterConverter : IValueConverter
/// <summary>
/// 正向转换器。将值从数据源传给绑定目标时，数据绑定引擎会调用此方法
/// </summary>
/// <param name="value">转换之前的值</param>
/// <param name="targetType">转换之后的数据类型</param>
/// <param name="parameter">转换器所使用的参数（它是通过 Binding 的 ConverterParameter 传递过来的）</param>
/// <param name="language">转换器所使用的区域信息（它是通过 Binding 的 ConverterLanguage 传递过来的）</param>
/// <returns>转换后的值</returns>
public object Convert(object value, Type targetType, object parameter, string language)
if (parameter != null && parameter.GetType() == typeof(TextBlock))
((TextBlock)parameter).Text = $"value: {value}, targetType: {targetType}, parameter: {parameter}, language: {language}";
int v = (int)(double)value;
return (char)v;
/// <summary>
/// 反向转换器。将值从绑定目标传给数据源时，数据绑定引擎会调用此方法
/// </summary>
/// <param name="value">转换之前的值</param>
/// <param name="targetType">转换之后的数据类型</param>
/// <param name="parameter">转换器所使用的参数（它是通过 Binding 的 ConverterParameter 传递过来的）</param>
/// <param name="language">转换器所使用的区域信息（它是通过 Binding 的 ConverterLanguage 传递过来的）</param>
/// <returns>转换后的值</returns>
public object ConvertBack(object value, Type targetType, object parameter, string language)
if (parameter != null && parameter.GetType() == typeof(TextBlock))
((TextBlock)parameter).Text = $"value: {value}, targetType: {targetType}, parameter: {parameter}, language: {language}";
int v = ((string)value).ToCharArray()[0];
return v;
