Silverlight MVVM模式开发 -MVVMLight

silverlight的mvvm模式框架有，MVVM Light:http://mvvmlight.codeplex.com 

Caliburn:http://caliburn.codeplex.com/

Prism:http://compositewpf.codeplex.com/

其中MVVMLight是一个轻量级框架，大家可以参考。下面重点说一下View与Command的原理及使用。

大家可以参照源代码：

1.每一个ViewModel都继承ViewModelBase类：大致的源代码是：

using System; using System.ComponentModel; using System.Linq.Expressions; namespace TAMS.Common { /// <summary> /// INotifyPropertyChanged的基类 /// </summary> public class PropertyChangedBase : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public void NotifyPropertyChanged(string propertyName) { if (this.PropertyChanged != null) { this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } } /// <summary> /// PropertyChangedBase的扩展方法 /// </summary> public static class PropertyChangedBaseEx { public static void NotifyPropertyChanged<T, TProperty>(this T propertyChangedBase, Expression<Func<T, TProperty>> expression) where T : PropertyChangedBase { var memberExpression = expression.Body as MemberExpression; if (memberExpression != null) { string propertyName = memberExpression.Member.Name; propertyChangedBase.NotifyPropertyChanged(propertyName); } else throw new NotImplementedException(); } } }
2. Command类的核心：

using System; using System.Windows.Input; namespace TAMS.Common { /// <summary> /// 功能描述：Silverlight 命令 代理类 /// 创 建 者：kntao /// 创建日期：2011/6/29 /// 修改记录： /// </summary> public class DelegateCommand : ICommand { /// <summary> /// Occurs when changes occur that affect whether the command should execute. /// </summary> public event EventHandler CanExecuteChanged; Func<object, bool> canExecute; Action<object> executeAction; bool canExecuteCache; /// <summary> /// Initializes a new instance of the <see cref="DelegateCommand"/> class. /// </summary> /// <param name="executeAction">The execute action.</param> /// <param name="canExecute">The can execute.</param> public DelegateCommand(Action<object> executeAction,Func<object, bool> canExecute) { this.executeAction = executeAction; this.canExecute = canExecute; } #region ICommand Members /// <summary> /// Defines the method that determines whether the command /// can execute in its current state. /// </summary> /// <param name="parameter"> /// Data used by the command. /// If the command does not require data to be passed, /// this object can be set to null. /// </param> /// <returns> /// true if this command can be executed; otherwise, false. /// </returns> public bool CanExecute(object parameter) { bool tempCanExecute = canExecute(parameter); if (canExecuteCache != tempCanExecute) { canExecuteCache = tempCanExecute; if (CanExecuteChanged != null) { CanExecuteChanged(this, new EventArgs()); } } return canExecuteCache; } /// <summary> /// Defines the method to be called when the command is invoked. /// </summary> /// <param name="parameter"> /// Data used by the command. /// If the command does not require data to be passed, /// this object can be set to null. /// </param> public void Execute(object parameter) { executeAction(parameter); } #endregion } } 3. 一个简单的运用：显示图书的列表，并可以通过图书内容进行搜索：

XAML文件：

<UserControl 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:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk" x:Class="MvvmLight1.MainPage" mc:Ignorable="d" Height="800" Width="1024" > <UserControl.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="Skins/MainSkin.xaml" /> </ResourceDictionary.MergedDictionaries> </ResourceDictionary> </UserControl.Resources> <UserControl.DataContext> <Binding Path="Main" Source="{StaticResource Locator}"/> </UserControl.DataContext> <Grid x:Name="LayoutRoot"> <TextBlock FontSize="36" FontWeight="Bold" Foreground="Purple" Text="{Binding Welcome}" VerticalAlignment="Center" HorizontalAlignment="Center" TextWrapping="Wrap" /> <TextBox x:Name="textBox" HorizontalAlignment="Left" Margin="32,24,0,0" TextWrapping="Wrap" Text="" VerticalAlignment="Top" Width="201" /> <Button Content="搜索" Margin="0,24,645,0" VerticalAlignment="Top" HorizontalAlignment="Right" Width="83" Command="{Binding SearchCommand, Mode=OneWay}" CommandParameter="{Binding Text, ElementName=textBox}" /> <sdk:DataGrid Margin="32,72,168,328" AutoGenerateColumns="False" ItemsSource="{Binding BookSource}" Height="400"> <sdk:DataGrid.Columns> <sdk:DataGridTextColumn Binding="{Binding BookIdBookId}" Header="图书编号"/> <sdk:DataGridTextColumn Binding="{Binding BookName}" Header="图书名称"/> <sdk:DataGridTextColumn Binding="{Binding BookAuthor}" Header="图书作者"/> </sdk:DataGrid.Columns> </sdk:DataGrid> </Grid> </UserControl> 大家可以通过Blend界面设置绑定属性，

2. ViewModel

using System.Collections.Generic; using GalaSoft.MvvmLight; using System.Windows.Input; using GalaSoft.MvvmLight.Command; using System.Linq; namespace MvvmLight1.ViewModel { /// <summary> /// This class contains properties that the main View can data bind to. /// <para> /// Use the <strong>mvvminpc</strong> snippet to add bindable properties to this ViewModel. /// </para> /// <para> /// You can also use Blend to data bind with the tool's support. /// </para> /// <para> /// See http://www.galasoft.ch/mvvm/getstarted /// </para> /// </summary> public class MainViewModel : ViewModelBase { private IList<BookInfo> _bookSource; #region 绑定属性 public IList<BookInfo> BookSource { get { return _bookSource; } set { if(_bookSource != value) { _bookSource = value; RaisePropertyChanged("BookSource"); } } } #endregion /// <summary> /// Initializes a new instance of the MainViewModel class. /// </summary> public MainViewModel() { if (IsInDesignMode) { // Code runs in Blend --> create design time data. } else { // Code runs "for real" BookSource = GetBooks(); SearchCommand = new RelayCommand<string>( (bookTitle) => { BookSource = GetBooks().Where(b => b.BookName.Contains(bookTitle)).ToList<BookInfo>(); } ); } } ////public override void Cleanup() ////{ //// // Clean up if needed //// base.Cleanup(); ////} #region Commands public ICommand SearchCommand { get; private set; } #endregion #region Data Source public class BookInfo { public int BookId { get; set; } public string BookName { get; set; } public string BookAuthor { get; set; } } public IList<BookInfo> GetBooks() { return new List<BookInfo> { new BookInfo() {BookId = 1, BookName = "CLR via C#（第3版）微软技术丛书", BookAuthor = "Richter"}, new BookInfo() {BookId = 2, BookName = "Windows Phone Mango开发实践", BookAuthor = "高雪松"}, new BookInfo() {BookId = 3, BookName = "C#本质论(第3版)", BookAuthor = "米凯利斯"}, new BookInfo() {BookId = 4, BookName = "ASP.NET本质论", BookAuthor = "郝冠军"}, new BookInfo() {BookId = 5, BookName = "Microsoft .NET企业级应用架构设计", BookAuthor = "埃斯波西托"}, new BookInfo() {BookId = 6, BookName = "你必须知道的.NET（第2版）", BookAuthor = "王涛"}, new BookInfo() {BookId = 7, BookName = "ASP.NET 4从入门到精通（微软技术丛书）", BookAuthor = "谢菲尔徳"}, new BookInfo() {BookId = 8, BookName = "ADO.NET 2.0技术内幕", BookAuthor = "斯塞帕（Sceppa，D.）"}, new BookInfo() {BookId = 9, BookName = "NET组件程序设计（第2版）", BookAuthor = "洛威（Lowy，J.）"}, new BookInfo(){BookId = 9, BookName = "庖丁解牛：纵向切入ASP.NET 3.5控件和组件开发技术（第2版）", BookAuthor = "郑健"} }; } #endregion } }

代码下载：http://download.csdn.net/download/kntao/3730030