Windows Phone 7 MVVM模式通讯方式之实现Attached Behavior

MVVM模式的View与ViewModel的三大通讯方式：Binding Data（实现数据的传递）、Command（实现操作的调用）和Attached
Behavior（实现控件加载过程中的操作）。

(1)Windows Phone 7 MVVM模式通讯方式之实现Binding Data。

(2)Windows Phone 7 MVVM模式通讯方式之实现Command。

(3)Windows Phone 7 MVVM模式通讯方式之实现Attached Behavior。

 

下面通过一个实例实现MVVM模式的Attached Behavior通讯，Attached Behavior与Command的区别就是，Attached Behavior在控件的加载过程中完成它的任务。

下面看一下实例的运行效果：

 

（1）MainPage.xaml页面代码，View层

<phone:PhoneApplicationPage 
    x:Class="AttachedBehaviorDemo.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:AttachedBehaviorDemo" 
    mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True">

    <Grid x:Name="LayoutRoot" Background="Transparent">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">
            <TextBlock x:Name="ApplicationTitle" Text="MY APPLICATION" Style="{StaticResource PhoneTextNormalStyle}"/>
            <TextBlock x:Name="PageTitle" Text="AttachedBehavior" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>
        </StackPanel>

        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
            <TextBlock FontSize="50" Text="金色 Gold" local:Behavior.Brush="Gold" Margin="0,6,0,504" />
            <TextBlock FontSize="50"  Text="绿色 Green" local:Behavior.Brush="Green" Margin="0,94,0,416" />
            <TextBlock FontSize="50"  Text="蓝色 Blue" local:Behavior.Brush="Blue" Margin="0,184,0,339" />
            <TextBlock FontSize="50"  Text="橙色 Orange" local:Behavior.Brush="Orange" Margin="-3,274,3,243" />
            <TextBlock FontSize="50"  Text="紫色 Purple" local:Behavior.Brush="Purple" Margin="0,386,0,133" />
            <TextBlock FontSize="50"  Text="橄榄色 Olive" local:Behavior.Brush="Olive" Margin="0,497,0,0" Height="110" VerticalAlignment="Top" />
        </Grid>
    </Grid>
    
</phone:PhoneApplicationPage>

（2）Behavior.cs类代码，处理附加的属性和事件。

using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;

namespace AttachedBehaviorDemo
{
    static public class Behavior
    {
        //注册一个附加属性BrushProperty，在XAML中名字为Brush，是Brush类型，在Hover类中，PropertyMetadata初始化元数据
        public static readonly DependencyProperty BrushProperty = DependencyProperty.RegisterAttached(
            "Brush",
            typeof(Brush),
            typeof(Behavior),
            new  PropertyMetadata (null, new PropertyChangedCallback(OnHoverBrushChanged)));

        /// <summary>
        /// 获取Brush的属性值
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static Brush GetBrush(DependencyObject obj)
        {
            return (Brush)obj.GetValue(BrushProperty);
        }
        /// <summary>
        /// 设置属性的值
        /// </summary>
        /// <param name="obj"></param>
        /// <param name="value"></param>
        public static void SetBrush(DependencyObject obj, Brush value)
        {
            obj.SetValue(BrushProperty, value);
        }
        /// <summary>
        /// 属性初始化
        /// </summary>
        /// <param name="obj"></param>
        /// <param name="args"></param>
        private static void OnHoverBrushChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
        {
            //获取属性所在的TextBlock控件
            TextBlock control = obj as TextBlock;
            //注册控件的事件
            if (control != null)
            {
                //注册鼠标进入事件
                control.MouseEnter += new MouseEventHandler(OnControlEnter);
                //注册鼠标离开事件
                control.MouseLeave += new MouseEventHandler(OnControlLeave);
            }

        }
        /// <summary>
        /// 鼠标进入事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        static void OnControlEnter(object sender, MouseEventArgs e)
        {
            //获取当前的TextBlock控件
            TextBlock control = (TextBlock)e.OriginalSource; 
            //设置控件的前景颜色为红色
            control.Foreground = new SolidColorBrush(Colors.Red);
        }

        /// <summary>
        /// 鼠标离开事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        static void OnControlLeave(object sender, MouseEventArgs e)
        {
            //获取当前的TextBlock控件
            TextBlock control = (TextBlock)e.OriginalSource;
            //设置控件的前景颜色为当前控件的Brush属性的值
            control.Foreground = GetBrush(control);
        } 

    }
}