/// <summary>
     /// 用戶信息
     /// </summary>
     public class UserInfoModel : ObservableObject
     {
         private String userName;
         /// <summary>
         /// 用戶名稱
         /// </summary>
         public String UserName
         {
             get { return userName; }
             set { userName = value; RaisePropertyChanged(()=>UserName); }
         }
         private Int64 userPhone;
         /// <summary>
         /// 用戶電話
         /// </summary>
         public Int64 UserPhone
         {
             get { return userPhone; }
             set { userPhone = value; RaisePropertyChanged(() => UserPhone); }
         }
         private Int32 userSex;
         /// <summary>
         /// 用戶性別
         /// </summary>
         public Int32 UserSex
         {
             get { return userSex; }
             set { userSex = value; RaisePropertyChanged(()=>UserSex); }
         }
         private String userAdd;
         /// <summary>
         /// 用戶地址
         /// </summary>
         public String UserAdd
         {
             get { return userAdd; }
             set { userAdd = value; RaisePropertyChanged(() => UserAdd); }
         }
    

    public class BothWayBindViewModel:ViewModelBase
     {
         public BothWayBindViewModel()
         {
             UserInfo = new UserInfoModel();
         }
         #region 屬性
         private UserInfoModel userInfo;
         /// <summary>
         /// 用戶信息
         /// </summary>
         public UserInfoModel UserInfo
         {
             get { return userInfo; }
             set { userInfo = value; RaisePropertyChanged(() => UserInfo); }
         }
         #endregion
         #region 命令
         #endregion
     }

/*
   In App.xaml:
   <Application.Resources>
       <vm:ViewModelLocator xmlns:vm="clr-namespace:MVVMLightDemo"
                            x:Key="Locator" />
   </Application.Resources>
   In the View:
   DataContext="{Binding Source={StaticResource Locator}, Path=ViewModelName}"
   You can also use Blend to do all this with the tool's support.
   See http://www.galasoft.ch/mvvm
 */
 
 using GalaSoft.MvvmLight;
 using GalaSoft.MvvmLight.Ioc;
 using Microsoft.Practices.ServiceLocation;
 namespace MVVMLightDemo.ViewModel
 {
     /// <summary>
     /// This class contains static references to all the view models in the
     /// application and provides an entry point for the bindings.
     /// </summary>
     public class ViewModelLocator
     {
         /// <summary>
         /// Initializes a new instance of the ViewModelLocator class.
         /// </summary>
         public ViewModelLocator()
         {
             ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);
             #region Code Example
             ////if (ViewModelBase.IsInDesignModeStatic)
             ////{
             ////    // Create design time view services and models
             ////    SimpleIoc.Default.Register<IDataService, DesignDataService>();
             ////}
             ////else
             ////{
             ////    // Create run time view services and models
             ////    SimpleIoc.Default.Register<IDataService, DataService>();
             ////}
             #endregion
             SimpleIoc.Default.Register<MainViewModel>();
             SimpleIoc.Default.Register<WelcomeViewModel>();
             SimpleIoc.Default.Register<BothWayBindViewModel>();    
         }
         #region 實例化
         public MainViewModel Main
         {
             get
             {
                 return ServiceLocator.Current.GetInstance<MainViewModel>();
             }
         }
         public WelcomeViewModel Welcome
         {
             get
             { 
                return ServiceLocator.Current.GetInstance<WelcomeViewModel>();
             }
         }
         public BothWayBindViewModel BothWayBind
         {
             get
             { 
                 return ServiceLocator.Current.GetInstance<BothWayBindViewModel>();
             }
         }     
         #endregion
         public static void Cleanup()
         {
             // TODO Clear the ViewModels
         }
     }

<Window x:Class="MVVMLightDemo.View.BothWayBindView"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         DataContext="{Binding Source={StaticResource Locator},Path=BothWayBind}"
         Title="BothWayBindView" Height="300" Width="300">
     <Grid>
             <StackPanel Orientation="Vertical" Margin="10,10,0,0">
                 <StackPanel Orientation="Horizontal" >
                     <TextBlock Text="請輸入姓名：" ></TextBlock>
                     <TextBox Text="{Binding UserInfo.UserName,UpdateSourceTrigger=PropertyChanged,Mode=TwoWay}" Width="200" ></TextBox>
                 </StackPanel>
 
                 <StackPanel Margin="0,10,0,0" Orientation="Horizontal" >
                     <TextBlock Text="Hello " ></TextBlock>
                     <TextBlock Text="{Binding UserInfo.UserName}" ></TextBlock>
                 </StackPanel>
 
                 <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center" Orientation="Horizontal" >
                 </StackPanel>
                 
             </StackPanel>
     </Grid>
</Window>