1. 新建WPF 应用程序WPFMVVMExample
2 Model实现
在Model文件夹下新建业务类StudentModel（类文件StudentModel.cs），类的详细代码如下所示。
using System;using System.Collections.Generic;using System.ComponentModel;using System.Linq;using System.Text;using System.Threading.Tasks;namespace WpfApp11.Model{public class StudentModel : INotifyPropertyChanged{/// <summary>/// 学号/// </summary>private int studentId;public int StudentId{get{return studentId;}set{studentId = value;NotifyPropertyChanged("StudentId");}}/// <summary>/// 姓名/// </summary>private string studentName;public string StudentName{get{return studentName;}set{studentName = value;NotifyPropertyChanged("StudentName");}}/// <summary>/// 年龄/// </summary>private int studentAge;public int StudentAge{get{return studentAge;}set{studentAge = value;NotifyPropertyChanged("StudentAge");}}/// <summary>/// </summary>private string studentEmail;public string StudentEmail{get{return studentEmail;}set{studentEmail = value;NotifyPropertyChanged("StudentEmail");}}/// <summary>/// 性别/// </summary>private string studentSex;public string StudentSex{get{return studentSex;}set{studentSex = value;NotifyPropertyChanged("StudentSex");}}public event PropertyChangedEventHandler PropertyChanged;public void NotifyPropertyChanged(string propertyName){if (PropertyChanged != null){PropertyChanged(this, new PropertyChangedEventArgs(propertyName));}}}}
StudentModel类实现了接口INotifyPropertyChanged。当类实现该接口后，便可以向执行绑定的客户端发出某一属性值已更改的通知。
3 ViewModel实现
在ViewModel文件夹下新建类文件StudentViewModel.cs,类文件的详细代码如下所示。
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Windows.Input;using WpfApp11.Model;namespace mvvm实例1.ViewModel{public class StudentViewModel{public DelegateCommand ShowCommand { get; set; }public StudentModel Student { get; set; }public StudentViewModel(){Student = new StudentModel();ShowCommand = new DelegateCommand();ShowCommand.ExecuteCommand = new Action<object>(ShowStudentData);}private void ShowStudentData(object obj){Student.StudentId = 1;Student.StudentName = "Csharp编程大全";Student.StudentAge = 20;Student.StudentEmail = "438679770@qq.com";Student.StudentSex = "男";}}public class DelegateCommand : ICommand{public Action<object> ExecuteCommand = null;public Func<object, bool> CanExecuteCommand = null;public event EventHandler CanExecuteChanged;public bool CanExecute(object parameter){if (CanExecuteCommand != null){return this.CanExecuteCommand(parameter);}else{return true;}}public void Execute(object parameter){if (this.ExecuteCommand != null){this.ExecuteCommand(parameter);}}public void RaiseCanExecuteChanged(){if (CanExecuteChanged != null){CanExecuteChanged(this, EventArgs.Empty);}}}}
代码中，除了定义StudentViewModel类外，还定义了DelegateCommand类，该类实现了ICommand接口。
ICommand接口中的Execute（）方法用于命令的执行，CanExecute（）方法用于指示当前命令在目标元素上是否可用，当这种可用性发生改变时便会触发接口中的CanExecuteChanged事件。
我们可以将实现了ICommand接口的命令DelegateCommand赋值给Button（命令源）的Command属性（只有实现了ICommandSource接口的元素才拥有该属性），这样Button便与命令进行了绑定。
4 MainWindow.xaml实现
MainWindow.xaml的界面如下图所示。
MainWindow.xaml界面的xaml代码如下所示。
<Window x:Class="WpfApp11.MainWindow"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"Title="MainWindow" Height="350" Width="525"><Grid><Label Content="学号" Height="28" HorizontalAlignment="Left" Margin="54,23,0,0" Name="labelStudentId" VerticalAlignment="Top" /><TextBox Text="{Binding Student.StudentId}" IsReadOnly="True" Height="23" HorizontalAlignment="Right" Margin="0,27,289,0" Name="textBoxStudentId" VerticalAlignment="Top" Width="120" /><Label Content="姓名" Height="28" HorizontalAlignment="Left" Margin="54,61,0,0" Name="labelStudentName" VerticalAlignment="Top" /><TextBox Text="{Binding Student.StudentName}" IsReadOnly="True" Height="23" HorizontalAlignment="Left" Margin="94,65,0,0" Name="textBoxStudentName" VerticalAlignment="Top" Width="120" /><Label Content="年龄" Height="28" HorizontalAlignment="Left" Margin="54,94,0,0" Name="labelStudentAge" VerticalAlignment="Top" /><TextBox Text="{Binding Student.StudentAge}" IsReadOnly="True" Height="23" HorizontalAlignment="Left" Margin="94,99,0,0" Name="textBoxStudentAge" VerticalAlignment="Top" Width="120" /><Label Content="Email" Height="28" HorizontalAlignment="Left" Margin="50,138,0,0" Name="labelStudentEmail" VerticalAlignment="Top" /><TextBox Text="{Binding Student.StudentEmail}" IsReadOnly="True" Height="23" HorizontalAlignment="Left" Margin="94,141,0,0" Name="textBoxStudentEmail" VerticalAlignment="Top" Width="120" /><Label Content="性别" Height="28" HorizontalAlignment="Left" Margin="57,176,0,0" Name="labelStudentSex" VerticalAlignment="Top" /><TextBox Text="{Binding Student.StudentSex}" IsReadOnly="True" Height="23" HorizontalAlignment="Left" Margin="94,180,0,0" Name="textBoxStudentSex" VerticalAlignment="Top" Width="120" /><Button Command="{Binding ShowCommand}" Content="显示" Height="23" HorizontalAlignment="Left" Margin="345,27,0,0" Name="buttonShow" VerticalAlignment="Top" Width="75" /></Grid></Window>
MainWindow.xaml的后端代码如下所示。
using mvvm实例1.ViewModel;using System.Windows;namespace WpfApp11{/// <summary>/// MainWindow.xaml 的交互逻辑/// </summary>public partial class MainWindow : Window{public MainWindow(){InitializeComponent();this.DataContext = new StudentViewModel();}}}
5 运行程序
运行程序，点击“显示”按钮，即将数据绑定至界面显示。
6 说明
WPF中使用MVVM可以降低UI显示与后端逻辑代码的耦合度，即更换界面时，只需要修改很少的逻辑代码就可以实现，甚至不用修改。
在WinForm开发中，我们一般会直接操作界面的元素（如：TextBox1.Text=“aaa”），这样一来，界面变化后，后端逻辑代码也需要做相应的变更。
在WPF中使用数据绑定机制，当数据变化后，数据会通知界面变更的发生，而不需要通过访问界面元素来修改值，这样在后端逻辑代码中也就不必操作或者很少操作界面的元素了。
使用MVVM，可以很好的配合WPF的数据绑定机制来实现UI与逻辑代码的分离，MVVM中的View表示界面，负责页面显示，ViewModel负责逻辑处理，包括准备绑定的数据和命令，ViewModel通过View的DataContext属性绑定至View，Model为业务模型，供ViewModel使用。
