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<Page    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="改變 listBox 的數(shù)據(jù)上下文" Click="btnChange_Click" Margin="5" />            <ListBox x:Name="listBox" ItemsSource="{Binding}" DataContextChanged="listBox_DataContextChanged" Background="Orange" Margin="5" />        </StackPanel>    </Grid></Page>

/* * DataContextChanged - FrameworkElement 的 DataContext 發(fā)生變化時(shí)觸發(fā)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)        {            // 指定數(shù)據(jù)上下文            listBox.DataContext = new List<string> { "a", "b", "c" };        }        private void btnChange_Click(object sender, RoutedEventArgs e)        {            // 修改數(shù)據(jù)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 - 數(shù)據(jù)上下文發(fā)生改變后觸發(fā)的事件             */            // 數(shù)據(jù)上下文發(fā)生改變后            lblMsg.Text = "數(shù)據(jù)上下文發(fā)生改變：" + DateTime.Now.ToString("hh:mm:ss");        }    }}

<Page    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 - 數(shù)據(jù)更新的觸發(fā)方式                    Default - 失去焦點(diǎn)后觸發(fā)                    PropertyChanged - 屬性值發(fā)生改變后觸發(fā)                    Explicit - 需要通過 BindingExpression.UpdateSource() 顯示觸發(fā)            -->            <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="顯示觸發(fā)更新" Click="btnBinding_Click" Margin="5" />        </StackPanel>    </Grid></Page>

/* * UpdateSourceTrigger - 數(shù)據(jù)更新的觸發(fā)方式 *     Default - 失去焦點(diǎn)后觸發(fā) *     PropertyChanged - 屬性值發(fā)生改變后觸發(fā) *     Explicit - 需要通過 BindingExpression.UpdateSource() 顯示觸發(fā) *      *      * BindingExpression - 綁定信息，可以通過 FrameworkElement 的 GetBindingExpression() 方法獲取指定屬性的綁定信息 *     DataItem - 獲取綁定的源對(duì)象 *     ParentBinding - 獲取綁定的 Binding 對(duì)象（Binding 對(duì)象里包括 ElementName, Path, Mode 等綁定信息） *     UpdateSource() - 將當(dāng)前值發(fā)送到 TwoWay 綁定的源對(duì)象的綁定的屬性中 */using System;using Windows.UI.Popups;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 async void btnBinding_Click(object sender, RoutedEventArgs e)        {            // 顯示觸發(fā) txtExplicit 的數(shù)據(jù)更新            BindingExpression be = txtExplicit.GetBindingExpression(TextBox.TextProperty);            be.UpdateSource();            // 獲取綁定的相關(guān)信息            Binding binding = be.ParentBinding;            TextBlock textBlock = be.DataItem as TextBlock;            MessageDialog messageDialog = new MessageDialog($"BindingExpression.DataItem:{textBlock.Name}, Binding.Mode:{binding.Mode}");            await messageDialog.ShowAsync();        }    }}

<Page    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 資源            -->            <StackPanel.Resources>                <local:IntegerLetterConverter x:Key="IntegerLetterConverter"/>                <local:FormatConverter x:Key="FormatConverter"/>                <x:String x:Key="FormatString">格式化字符串 {0}</x:String>            </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 不支持綁定，只能配置為一個(gè)靜態(tài)的值（但是在 C# 端可以實(shí)現(xiàn)一些在 xaml 中無法實(shí)現(xiàn)的特性，詳見后面的例子）            -->            <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" Margin="5" TextWrapping="Wrap" />            <!--                演示如何在 ConverterParameter 中通過 {0} 格式化字符串             -->            <TextBlock Name="textBlock1" Text="我是“textBlock1”" Margin="5" />            <TextBlock Name="textBlock2" Margin="5" Text="{Binding ElementName=textBlock1, Path=Text,                                                                   Converter={StaticResource FormatConverter},                                                                   ConverterParameter={StaticResource FormatString}}" />        </StackPanel>    </Grid></Page>

/* * 演示如何對(duì)綁定的數(shù)據(jù)做自定義轉(zhuǎn)換 */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)        {            // 實(shí)例化 Binding 對(duì)象            Binding binding = new Binding()            {                ElementName = nameof(slider2),                Path = new PropertyPath(nameof(Slider.Value)),                Mode = BindingMode.TwoWay, // 默認(rèn)是 OneWay 的                Converter = new IntegerLetterConverter(),                ConverterParameter = lblMsg, // 將 ConverterParameter 設(shè)置為一個(gè)指定的控件，這個(gè)在 xaml 中實(shí)現(xiàn)不了，但是可以在 C# 端實(shí)現(xiàn)                ConverterLanguage = "zh"            };            // 將目標(biāo)對(duì)象的目標(biāo)屬性與指定的 Binding 對(duì)象關(guān)聯(lián)            BindingOperations.SetBinding(textBox2, TextBox.TextProperty, binding);        }    }    // 自定義一個(gè)實(shí)現(xiàn)了 IValueConverter 接口的類，用于對(duì)綁定的數(shù)據(jù)做自定義轉(zhuǎn)換    public sealed class IntegerLetterConverter : IValueConverter    {        /// <summary>        /// 正向轉(zhuǎn)換器。將值從數(shù)據(jù)源傳給綁定目標(biāo)時(shí)，數(shù)據(jù)綁定引擎會(huì)調(diào)用此方法        /// </summary>        /// <param name="value">轉(zhuǎn)換之前的值</param>        /// <param name="targetType">轉(zhuǎn)換之后的數(shù)據(jù)類型</param>        /// <param name="parameter">轉(zhuǎn)換器所使用的參數(shù)（它是通過 Binding 的 ConverterParameter 傳遞過來的）</param>        /// <param name="language">轉(zhuǎn)換器所使用的區(qū)域信息（它是通過 Binding 的 ConverterLanguage 傳遞過來的）</param>        /// <returns>轉(zhuǎn)換后的值</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>        /// 反向轉(zhuǎn)換器。將值從綁定目標(biāo)傳給數(shù)據(jù)源時(shí)，數(shù)據(jù)綁定引擎會(huì)調(diào)用此方法        /// </summary>        /// <param name="value">轉(zhuǎn)換之前的值</param>        /// <param name="targetType">轉(zhuǎn)換之后的數(shù)據(jù)類型</param>        /// <param name="parameter">轉(zhuǎn)換器所使用的參數(shù)（它是通過 Binding 的 ConverterParameter 傳遞過來的）</param>        /// <param name="language">轉(zhuǎn)換器所使用的區(qū)域信息（它是通過 Binding 的 ConverterLanguage 傳遞過來的）</param>        /// <returns>轉(zhuǎn)換后的值</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;        }    }    // 自定義一個(gè)實(shí)現(xiàn)了 IValueConverter 接口的類，用于格式化字符串    public sealed class FormatConverter : IValueConverter    {        public object Convert(object value, Type targetType, object parameter, string language)        {            string format = (string)parameter;            return string.Format(format, value);        }        public object ConvertBack(object value, Type targetType, object parameter, string language)        {            throw new NotImplementedException();        }    }}