SilverLight:在MVVM中实现多事件

在开发Silverlight项目时，如果使用了MVVM架构时，可以实现业务逻辑与界面的完全分离。事件可以通过实现接口ICommand达到效果，比如：Button控件，如果要实现单击效果时，可以通过绑定Command即可。

　　但是如果需要实现鼠标离开Button事件怎么实现呢，就这是今天需要讨论的问题=》多事件实现

　　项目架构如下图：

　　我今天主要用Button做实验，来实现Button控件的单击事件和鼠标离开事件。这在非MVVM架构下非常容易实现。但是在MVVM架构，我们需要引用System.Windows.Interactivity.dll,此动态库存放的位置为C:/Program Files/Microsoft SDKs/Expression/Blend 3/Interactivity/Libraries/Silverlight/System.Windows.Interactivity.dll

　　关于System.Windows.Interactivity.dll的介绍，请查看http://msdn.microsoft.com/zh-cn/library/system.windows.interactivity(v=Expression.40).aspx

　　通过引用动态库，然后在MainPage.xaml中实现Button的两个事件。代码如下:

　　MainPage.xaml

< UserControl x:Class = " MoreEvent.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:i = " http://schemas.microsoft.com/expression/2010/interactivity "
    xmlns:local = " clr-namespace:MoreEventviewmodel;assembly=MoreEventviewmodel "
    mc:Ignorable = " d "
    d:DesignHeight = " 300 " d:DesignWidth = " 400 " >
     < UserControl.Resources >
         < local:MoreEventsviewmodel x:Key = " k " />
     </ UserControl.Resources >
     < Grid x:Name = " LayoutRoot " Background = " White " DataContext = " {StaticResource k} " >
         < Button Content = " 测试多事件 " Width = " 70 " Height = " 25 " >
             < i:Interaction.Triggers >
                 < i:EventTrigger EventName = " Click " >
                     < i:InvokeCommandAction Command = " {Binding BtnClick} " />
                 </ i:EventTrigger >
                 < i:EventTrigger EventName = " MouseLeave " >
                     < i:InvokeCommandAction Command = " {Binding MouseLeave} " />
                 </ i:EventTrigger >
             </ i:Interaction.Triggers >
         </ Button >
     </ Grid >
</ UserControl >

　　那么viewmodel和ICommand的实现非常简单，两个文件的代码如下

　　MoreEventsviewmodel.cs

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace MoreEventviewmodel
{
     public class MoreEventsviewmodel
    {
         public MoreEventsviewmodel()
        {

        }

         private void MouseLeaveEvent( object obj)
        {
            MessageBox.Show( " 测试鼠标离开事件 " );
        }
         private void BtnClickEvent( object obj)
        {
            MessageBox.Show( " 测试单击事件 " );
        }

         public ICommand MouseLeave
        {
             get { return new MoreEventCommand(MouseLeaveEvent); }
        }
         public ICommand BtnClick
        {
             get { return new MoreEventCommand(BtnClickEvent); }
        }
    }
}

　MoreEventCommand.cs

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace MoreEventviewmodel
{
     public class MoreEventCommand:ICommand
    {
        Action < object > _action;
         public MoreEventCommand(Action < object > ac)
        {
            _action = ac;
        }
         public bool CanExecute( object parameter)
        {
             return true ;
        }

         public event EventHandler CanExecuteChanged;

         public void Execute( object parameter)
        {
             if (_action != null )
                _action(parameter);
        }
    }
}

　　通过以上方法即可在MVVM实现多事件.通过这个件事，大家可以触类旁通，实现其它控件的多事件。希望对大家有用。

本文来自天神一的博客，原文地址：http://www.cnblogs.com/888h/archive/2010/12/08/1900621.html

SilverLight:在MVVM中实现多事件

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