重新想象 Windows 8 Store Apps (16)

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重新想象 Windows 8 Store Apps (16) - 控件基础: 依赖属性, 附加属性, 控件的继承关系, 路由事件和命中测试

作者：webabcd


介绍
重新想象 Windows 8 Store Apps 之 控件基础

• DependencyProperty - 依赖属性
• AttachedProperty - 附加属性
• 控件的继承关系
• 路由事件和命中测试

示例
1、开发一个具有 DependencyProperty 和 AttachedProperty 的自定义控件
MyControls/themes/generic.xaml

<ResourceDictionary    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"    xmlns:local="using:MyControls">    <!--        自定义控件的样式在本文件（themes/generic.xaml）中定义            整合外部 ResourceDictionary    -->    <ResourceDictionary.MergedDictionaries>        <ResourceDictionary Source="ms-appx:///MyControls/themes/MyControl.xaml"/>    </ResourceDictionary.MergedDictionaries>   </ResourceDictionary>

MyControls/themes/MyControl.xaml

<ResourceDictionary    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"    xmlns:local="using:MyControls">    <Style TargetType="local:MyControl">        <Setter Property="Template">            <Setter.Value>                <ControlTemplate TargetType="local:MyControl">                    <Border Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}">                        <StackPanel>                            <!--绑定自定义依赖属性-->                            <TextBlock Text="{TemplateBinding Title}" Foreground="White" FontSize="26.667" />                            <!--绑定自定义附加属性-->                            <TextBlock Text="{TemplateBinding local:MyAttachedProperty.SubTitle}" Foreground="White" FontSize="14.667" />                        </StackPanel>                    </Border>                </ControlTemplate>            </Setter.Value>        </Setter>    </Style></ResourceDictionary>

MyControls/MyControl.cs

/* * 开发一个自定义控件，用于演示依赖属性（Dependency Property）和附加属性（Attached Property） *  * 依赖属性：可以用于样式, 模板, 绑定, 动画 * 附加属性：全局可用的依赖属性 */using Windows.UI.Xaml.Controls;using Windows.UI.Xaml;namespace MyControls{    /// <summary>    /// 用于依赖属性的演示    /// </summary>    public class MyControl : Control    {        public MyControl()        {            // 指定默认样式为 typeof(MyControl)，即对应：<Style xmlns:local="using:MyControls" TargetType="local:MyControl" />            this.DefaultStyleKey = typeof(MyControl);        }        // 通过 DependencyObject.GetValue() 和 DependencyObject.SetValue() 访问依赖属性，这里由 Title 属性封装一下，以方便对依赖属性的访问        public string Title        {            get { return (string)GetValue(TitleProperty); }            set { SetValue(TitleProperty, value); }        }        // 注册一个依赖属性        public static readonly DependencyProperty TitleProperty =            DependencyProperty.Register(                "Title", // 依赖属性的名称                typeof(string),  // 依赖属性的数据类型                typeof(MyControl),  // 依赖属性所属的类                new PropertyMetadata("", PropertyMetadataCallback)); // 指定依赖属性的默认值，以及值发生改变时所调用的方法        private static void PropertyMetadataCallback(DependencyObject sender, DependencyPropertyChangedEventArgs args)        {            object newValue = args.NewValue; // 发生改变之后的值            object oldValue = args.OldValue; // 发生改变之前的值        }    }    /// <summary>    /// 用于附加属性的演示    /// </summary>    public class MyAttachedProperty    {        // 获取附加属性        public static string GetSubTitle(DependencyObject obj)        {            return (string)obj.GetValue(SubTitleProperty);        }        // 设置附加属性        public static void SetSubTitle(DependencyObject obj, string value)        {            obj.SetValue(SubTitleProperty, value);        }        // 注册一个附加属性        public static readonly DependencyProperty SubTitleProperty =            DependencyProperty.RegisterAttached(                "SubTitle", // 附加属性的名称                typeof(string), // 附加属性的数据类型                typeof(MyAttachedProperty), // 附加属性所属的类                new PropertyMetadata("", PropertyMetadataCallback)); // 指定附加属性的默认值，以及值发生改变时所调用的方法        private static void PropertyMetadataCallback(DependencyObject sender, DependencyPropertyChangedEventArgs args)        {            object newValue = args.NewValue; // 发生改变之后的值            object oldValue = args.OldValue; // 发生改变之前的值        }    }}

2、演示依赖属性的使用
Controls/Basic/DependencyPropertyDemo.xaml

<Page    x:Class="XamlDemo.Controls.Basic.DependencyPropertyDemo"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"    xmlns:local="using:XamlDemo.Controls.Basic"    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"    xmlns:myControls="using:MyControls"    mc:Ignorable="d">    <Grid Background="Transparent">        <StackPanel Margin="120 0 0 0">                        <!--                演示如何开发和使用自定义依赖属性（本例所用到的自定义控件请参看：MyControls/MyControl.cs）            -->            <myControls:MyControl Background="Blue" BorderBrush="Yellow" BorderThickness="1" Width="100" HorizontalAlignment="Left"                                  Title="{Binding Value, ElementName=slider}" />            <Slider Name="slider" Width="100" Minimum="0" Maximum="200" IsThumbToolTipEnabled="False"  HorizontalAlignment="Left" />        </StackPanel>    </Grid></Page>

3、演示附加属性的使用
Controls/Basic/AttachedPropertyDemo.xaml

<Page    x:Class="XamlDemo.Controls.Basic.AttachedPropertyDemo"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"    xmlns:local="using:XamlDemo.Controls.Basic"    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"    xmlns:myControls="using:MyControls"    mc:Ignorable="d">    <Grid Background="Transparent">        <StackPanel Margin="120 0 0 0">            <!--                演示如何开发和使用自定义附加属性（本例所用到的自定义控件请参看：MyControls/MyControl.cs）            -->            <myControls:MyControl Background="Blue" BorderBrush="Yellow" BorderThickness="1" Width="100" HorizontalAlignment="Left"                                  Title="{Binding Value, ElementName=slider}" myControls:MyAttachedProperty.SubTitle="{Binding Value, ElementName=slider}" />            <Slider Name="slider" Width="100" Minimum="0" Maximum="200" IsThumbToolTipEnabled="False"  HorizontalAlignment="Left" />                    </StackPanel>    </Grid></Page>

4、控件的继承关系的概述
Controls/Basic/Inherit.xaml

<Page    x:Class="XamlDemo.Controls.Basic.Inherit"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"    xmlns:local="using:XamlDemo.Controls.Basic"    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="120 0 0 0">            <TextBlock Name="lblMsg" FontSize="14.667" LineHeight="25">                <Run>继承关系: FrameworkElement -> UIElement -> DependencyObject</Run>                <LineBreak />                <Run>DependencyObject - 提供对依赖属性的访问，以及获取此对象关联的 CoreDispatcher</Run>                <LineBreak />                <Run>UIElement - 可视元素，键盘和鼠标输入等</Run>                <LineBreak />                <Run>FrameworkElement - 框架元素，数据绑定，一些公共 API 等。例：Control, TextBlock, WebView 等继承自 FrameworkElement</Run>                <LineBreak />                <Run>ContentControl - 其内包含有一个内容，继承自 Control。例：ScrollViewer, AppBar 等继承自 ContentControl</Run>                <LineBreak />                <Run>ButtonBase - 按钮的基本功能，继承自 ContentControl。例：Button, RepeatButton 等继承自 ButtonBase</Run>                <LineBreak />                <Run>ToggleButton - 可切换状态的按钮，继承自 ButtonBase。例：RadioButton, CheckBox 等继承自 ToggleButton</Run>                <LineBreak />                <Run>RangeBase - 值在某一范围内，继承自 ButtonBase。例：ProgressBar, Slider, ScrollBar 等继承自 RangeBase</Run>                <LineBreak />                <Run>ItemsControl - 用于呈现集合，继承自 Control</Run>                <LineBreak />                <Run>Selector - 可选择集合中的某一项，继承自 ItemsControl。例：ComboBox, ListBox, FlipView, ListViewBase 等继承自 Selector</Run>                <LineBreak />                <Run>ListViewBase - 继承自 ListViewBase 的控件有 GridView 和 ListView</Run>                <LineBreak />                <Run>Panel - 一个容器，继承自 FrameworkElement。例：Grid, StackPanel, Canvas 等继承自 Panel</Run>                <LineBreak />                <Run>如 ScrollBar, Thumb, RangeBase, ButtonBase, Selector, Popup 等这类基元控件在 Windows.UI.Xaml.Controls.Primitives 命名空间下</Run>            </TextBlock>        </StackPanel>    </Grid></Page>

5、路由事件和命中测试
Controls/Basic/RoutedEventDemo.xaml

<Page    x:Class="XamlDemo.Controls.Basic.RoutedEventDemo"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"    xmlns:local="using:XamlDemo.Controls.Basic"    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="120 0 0 0">            <Grid HorizontalAlignment="Left" VerticalAlignment="Top">                <!--                    演示事件冒泡：儿子传递事件给爸爸，爸爸传递事件给爷爷，这就是事件冒泡                -->                <Border Name="borderRed" Background="Red" Width="300" Height="300">                    <Border Name="borderGreen" Background="Green" Width="250" Height="250" Tapped="borderGreen_Tapped_1">                        <Border Name="borderBlue" Background="Blue" Width="200" Height="200" Tapped="borderBlue_Tapped_1">                            <Border Name="borderOrange" Background="Orange" Width="150" Height="150" Tapped="borderOrange_Tapped_1">                                <!--命中测试不可见，也就是说 borderPurple 和 borderYellow 均命中测试不可见-->                                <Border Name="borderPurple" Background="Purple" Width="100" Height="100" Tapped="borderPurple_Tapped_1" IsHitTestVisible="False">                                    <Border Name="borderYellow" Background="Yellow" Width="50" Height="50" Tapped="borderYellow_Tapped_1" />                                </Border>                            </Border>                        </Border>                    </Border>                </Border>                                <!--                    像这样排列元素，是没有事件冒泡的，而只是前面的元素响应事件，后面的元素不会响应事件，也就是说同辈间没有事件冒泡的概念                    IsHitTestVisible - 是否对命中测试可见                    <Rectangle Name="rectangle1" Width="800" Height="400" Fill="Red" />                    <Rectangle Name="rectangle2" Width="700" Height="350" Fill="Green" />                    <Rectangle Name="rectangle3" Width="600" Height="300" Fill="Blue" />                    <Rectangle Name="rectangle4" Width="500" Height="250" Fill="Orange" />                    <Rectangle Name="rectangle5" Width="400" Height="200" Fill="Purple" />                -->            </Grid>            <TextBlock Name="lblMsg" FontSize="14.667" Margin="0 10 0 0" />        </StackPanel>    </Grid></Page>

Controls/Basic/RoutedEventDemo.xaml.cs

/* * 演示路由事件的冒泡和命中测试的可见性 *  * TappedRoutedEventArgs *     OriginalSource - 引发此路由事件的对象 *     Handled - 是否将路由事件标记为已处理 *         true - 不再冒泡 *         false - 继续冒泡 *      * UIElement *     IsHitTestVisible - 是否对命中测试可见 */using System;using Windows.UI.Xaml;using Windows.UI.Xaml.Controls;using Windows.UI.Xaml.Input;namespace XamlDemo.Controls.Basic{    public sealed partial class RoutedEventDemo : Page    {        public RoutedEventDemo()        {            this.InitializeComponent();            // AddHandler() - 注册一个路由事件，注意最后一个参数：true 代表即使子辈 TappedRoutedEventArgs.Handled = true 也不会影响此元素事件的触发            // RemoveHandler() - 移除指定的路由事件            borderRed.AddHandler(UIElement.TappedEvent, new TappedEventHandler(borderRed_Tapped_1), true);        }        private void borderRed_Tapped_1(object sender, TappedRoutedEventArgs e)        {            lblMsg.Text += "borderRed tapped, originalSource: " + (e.OriginalSource as FrameworkElement).Name;            lblMsg.Text += Environment.NewLine;        }        private void borderGreen_Tapped_1(object sender, TappedRoutedEventArgs e)        {            lblMsg.Text += "borderGreen tapped, originalSource: " + (e.OriginalSource as FrameworkElement).Name;            lblMsg.Text += Environment.NewLine;        }        private void borderBlue_Tapped_1(object sender, TappedRoutedEventArgs e)        {            lblMsg.Text += "borderBlue tapped, originalSource: " + (e.OriginalSource as FrameworkElement).Name;            lblMsg.Text += Environment.NewLine;            // 不会再冒泡，也就是说 borderGreen 无法响应 Tapped 事件，但是 borderRed 注册 Tapped 事件时 handledEventsToo = true，所以 borderRed 会响应 Tapped 事件            e.Handled = true;        }        private void borderOrange_Tapped_1(object sender, TappedRoutedEventArgs e)        {            lblMsg.Text += "borderOrange tapped, originalSource: " + (e.OriginalSource as FrameworkElement).Name;            lblMsg.Text += Environment.NewLine;        }        private void borderPurple_Tapped_1(object sender, TappedRoutedEventArgs e)        {            // 不会响应此事件，因为 borderPurple 的 IsHitTestVisible = false            lblMsg.Text += "borderPurple tapped, originalSource: " + (e.OriginalSource as FrameworkElement).Name;            lblMsg.Text += Environment.NewLine;        }        private void borderYellow_Tapped_1(object sender, TappedRoutedEventArgs e)        {            // 不会响应此事件，因为 borderYellow 的爸爸 borderPurple 的 IsHitTestVisible = false            lblMsg.Text += "borderYellow tapped, originalSource: " + (e.OriginalSource as FrameworkElement).Name;            lblMsg.Text += Environment.NewLine;        }    }}

OK
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