Windows Phone 7 MVVM模式通讯方式之实现Command

（1）MainPage.xaml文件的代码,实现View层

 
 


  
  
 

  
  
<phone:PhoneApplicationPage 

  
  
 

  
  
    x:Class="CommandDemo.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:my="clr-namespace:CommandDemo.ViewModel" 

  
  
 

  
  
    xmlns:my_Interactivity="clr-namespace:CommandDemo.Command" 

  
  
 

  
  
    xmlns:Custom="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity" xmlns:ic="clr-namespace:Microsoft.Expression.Interactivity.Core;assembly=Microsoft.Expression.Interactions" 

  
  
 

  
  
    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"> 

  
  
 

  
  
    <!--设置整个页面的上下文数据DataContext为RadiusViewModel--> 

  
  
 

  
  
    <phone:PhoneApplicationPage.DataContext> 

  
  
 

  
  
        <my:RadiusViewModel/> 

  
  
 

  
  
    </phone:PhoneApplicationPage.DataContext> 

  
  
 

  
  
   

  
  
 

  
  
    <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="Command" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/> 

  
  
 

  
  
        </StackPanel> 

  
  
 

  
  
   

  
  
 

  
  
   

  
  
 

  
  
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0"> 

  
  
 

  
  
            <Ellipse Fill="Red" 

  
  
 

  
  
                     Height="{Binding Radius}" Width="{Binding Radius}" 

  
  
 

  
  
                     HorizontalAlignment="Left" Margin="119,84,0,0" Name="ellipse1" Stroke="Black" StrokeThickness="1" VerticalAlignment="Top" /> 

  
  
 

  
  
            <Button Content="小" Height="72" HorizontalAlignment="Left" Margin="0,385,0,0" Name="button1" VerticalAlignment="Top" Width="160"> 

  
  
 

  
  
                <Custom:Interaction.Triggers> 

  
  
 

  
  
                    <Custom:EventTrigger EventName="Click"> 

  
  
 

  
  
                        <my_Interactivity:ExecuteCommandAction CommandName="MinRadius"/> 

  
  
 

  
  
                    </Custom:EventTrigger> 

  
  
 

  
  
                </Custom:Interaction.Triggers> 

  
  
 

  
  
            </Button> 

  
  
 

  
  
            <Button Content="中" Height="72" HorizontalAlignment="Left" Margin="149,384,0,0" Name="button2" VerticalAlignment="Top" Width="160" > 

  
  
 

  
  
                <Custom:Interaction.Triggers> 

  
  
 

  
  
                    <Custom:EventTrigger EventName="Click"> 

  
  
 

  
  
                        <my_Interactivity:ExecuteCommandAction CommandName="MedRadius"/> 

  
  
 

  
  
                    </Custom:EventTrigger> 

  
  
 

  
  
                </Custom:Interaction.Triggers> 

  
  
 

  
  
            </Button> 

  
  
 

  
  
            <Button Content="大" Height="72" HorizontalAlignment="Left" Margin="299,382,0,0" Name="button3" VerticalAlignment="Top" Width="160" > 

  
  
 

  
  
                <Custom:Interaction.Triggers> 

  
  
 

  
  
                    <Custom:EventTrigger EventName="Click"> 

  
  
 

  
  
                        <my_Interactivity:ExecuteCommandAction  CommandName="MaxRadius"/> 

  
  
 

  
  
                    </Custom:EventTrigger> 

  
  
 

  
  
                </Custom:Interaction.Triggers> 

  
  
 

  
  
            </Button> 

  
  
 

  
  
        </Grid> 

  
  
 

  
  
    </Grid> 

  
  
 

  
  
   

  
  
 

  
  
</phone:PhoneApplicationPage> 
 
 

（2）RadiusViewModel.cs文件的代码,实现ViewModel层

 
 


  
  
 

  
  
using System;  

  
  
 

  
  
using System.Windows.Input;  

  
  
 

  
  
using System.ComponentModel;  

  
  
 

  
  
using Microsoft.Expression.Interactivity.Core;  

  
  
 

  
  
   

  
  
 

  
  
namespace CommandDemo.ViewModel  

  
  
 

  
  
{  

  
  
 

  
  
    public class RadiusViewModel : INotifyPropertyChanged  

  
  
 

  
  
    {  

  
  
 

  
  
        private Double radius;  

  
  
 

  
  
   

  
  
 

  
  
        public RadiusViewModel()  

  
  
 

  
  
        {  

  
  
 

  
  
            Radius = 0;  

  
  
 

  
  
            MinRadius = new ActionCommand(p => Radius = 100);  

  
  
 

  
  
            MedRadius = new ActionCommand(p => Radius = 200);  

  
  
 

  
  
            MaxRadius = new ActionCommand(p => Radius = 300);  

  
  
 

  
  
        }  

  
  
 

  
  
   

  
  
 

  
  
        public event PropertyChangedEventHandler PropertyChanged;  

  
  
 

  
  
   

  
  
 

  
  
        public ICommand MinRadius  

  
  
 

  
  
        {  

  
  
 

  
  
            get; private set;  

  
  
 

  
  
        }  

  
  
 

  
  
   

  
  
 

  
  
        public ICommand MedRadius  

  
  
 

  
  
        {  

  
  
 

  
  
            get;  

  
  
 

  
  
            private set;  

  
  
 

  
  
        }  

  
  
 

  
  
   

  
  
 

  
  
        public ICommand MaxRadius  

  
  
 

  
  
        {  

  
  
 

  
  
            get;  

  
  
 

  
  
            private set;  

  
  
 

  
  
        }  

  
  
 

  
  
   

  
  
 

  
  
        public Double Radius  

  
  
 

  
  
        {  

  
  
 

  
  
            get  

  
  
 

  
  
            {  

  
  
 

  
  
                return radius;  

  
  
 

  
  
            }  

  
  
 

  
  
            set  

  
  
 

  
  
            {  

  
  
 

  
  
                radius = value;  

  
  
 

  
  
                OnPropertyChanged("Radius");  

  
  
 

  
  
            }  

  
  
 

  
  
        }  

  
  
 

  
  
   

  
  
 

  
  
        protected virtual void OnPropertyChanged(string propertyName)  

  
  
 

  
  
        {  

  
  
 

  
  
            var propertyChanged = PropertyChanged;  

  
  
 

  
  
   

  
  
 

  
  
            if(propertyChanged != null)  

  
  
 

  
  
                propertyChanged(this, new PropertyChangedEventArgs(propertyName));  

  
  
 

  
  
        }  

  
  
 

  
  
    }  

  
  
 

  
  
} 
 
 

（3）ExecuteCommandAction.cs类，实现Command操作

 
 


  
  
 

  
  
using System;  

  
  
 

  
  
using System.Windows;  

  
  
 

  
  
using System.Windows.Input;  

  
  
 

  
  
using System.Windows.Interactivity;  

  
  
 

  
  
using System.Reflection;  

  
  
 

  
  
   

  
  
 

  
  
namespace CommandDemo.Command  

  
  
 

  
  
{  

  
  
 

  
  
    public class ExecuteCommandAction : TriggerAction<FrameworkElement> 

  
  
 

  
  
    {  

  
  
 

  
  
        public static readonly DependencyProperty CommandNameProperty =  

  
  
 

  
  
             DependencyProperty.Register("CommandName", typeof(string), typeof(ExecuteCommandAction), null);  

  
  
 

  
  
   

  
  
 

  
  
        public static readonly DependencyProperty CommandParameterProperty =  

  
  
 

  
  
            DependencyProperty.Register("CommandParameter", typeof(object), typeof(ExecuteCommandAction), null);  

  
  
 

  
  
   

  
  
 

  
  
        protected override void Invoke(object parameter)  

  
  
 

  
  
        {  

  
  
 

  
  
            if (AssociatedObject == null)  

  
  
 

  
  
                return;  

  
  
 

  
  
   

  
  
 

  
  
            ICommand command = null;  

  
  
 

  
  
   

  
  
 

  
  
            var dataContext = AssociatedObject.DataContext;  

  
  
 

  
  
   

  
  
 

  
  
            foreach (var info in dataContext.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance))  

  
  
 

  
  
            {  

  
  
 

  
  
                if (IsCommandProperty(info) && String.Equals(info.Name, CommandName, StringComparison.Ordinal))  

  
  
 

  
  
                {  

  
  
 

  
  
                    command = (ICommand)info.GetValue(dataContext, null);  

  
  
 

  
  
                    break;  

  
  
 

  
  
                }  

  
  
 

  
  
            }  

  
  
 

  
  
   

  
  
 

  
  
            if ((command != null) && command.CanExecute(CommandParameter))  

  
  
 

  
  
            {  

  
  
 

  
  
                command.Execute(CommandParameter);  

  
  
 

  
  
            }  

  
  
 

  
  
        }  

  
  
 

  
  
   

  
  
 

  
  
        private static bool IsCommandProperty(PropertyInfo property)  

  
  
 

  
  
        {  

  
  
 

  
  
            return typeof(ICommand).IsAssignableFrom(property.PropertyType);  

  
  
 

  
  
        }  

  
  
 

  
  
   

  
  
 

  
  
        public string CommandName  

  
  
 

  
  
        {  

  
  
 

  
  
            get  

  
  
 

  
  
            {  

  
  
 

  
  
                return (string)GetValue(CommandNameProperty);  

  
  
 

  
  
            }  

  
  
 

  
  
            set  

  
  
 

  
  
            {  

  
  
 

  
  
                SetValue(CommandNameProperty, value);  

  
  
 

  
  
            }  

  
  
 

  
  
        }  

  
  
 

  
  
   

  
  
 

  
  
        public object CommandParameter  

  
  
 

  
  
        {  

  
  
 

  
  
            get  

  
  
 

  
  
            {  

  
  
 

  
  
                return GetValue(CommandParameterProperty);  

  
  
 

  
  
            }  

  
  
 

  
  
            set  

  
  
 

  
  
            {  

  
  
 

  
  
                SetValue(CommandParameterProperty, value);  

  
  
 

  
  
            }  

  
  
 

  
  
        }  

  
  
 

  
  
    }  

  
  
 

  
  
} 
 
 

本文转自linzheng 51CTO博客，原文链接:http://blog.51cto.com/linzheng/1078577