MVVMLight：
使用NUGET安装MVVMLight包后，会自动生成ViewModel文件夹，里面包含一个ViewModelLocator，在这个文件中，使用依赖注入的方式，添加对ViewModel的注册，然后在.xaml文件中引入。这样做的好处，
1：一个view可以注册多个viewmodel，
2：从.XAML文件中引入，在界面会及时显示出绑定的数据，友好界面调整。
3：切换页面的时候，数据可以缓存的，因为在ViewModelLocator中，ServiceLocator.Current.GetInstance(class)这个方法是通过单例模式注册获取的。就是说，ViewModel类中定义的属性值是一直存在。
如果是在.cs文件中通过 DataContext=new xxxViewModel();关联ViewModel类，每次都会new一个新的初始化的类。
public class ViewModelLocator
/// <summary>
/// Initializes a new instance of the ViewModelLocator class.
/// </summary>
public ViewModelLocator()
ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);
////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>();
////}
SimpleIoc.Default.Register<MainViewModel>();
SimpleIoc.Default.Register<WelcomeViewModel>();
SimpleIoc.Default.Register<BothWayBindViewModel>();
public MainViewModel Main
return ServiceLocator.Current.GetInstance<MainViewModel>();
public WelcomeViewModel Welcome
return ServiceLocator.Current.GetInstance<WelcomeViewModel>();
public BothWayBindViewModel BothWayBind
return ServiceLocator.Current.GetInstance<BothWayBindViewModel>();
public static void Cleanup()
// TODO Clear the ViewModels
View Code
<Window x:Class="WPF_MVVMLight.BothWayBindView"
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:local="clr-namespace:WPF_MVVMLight"
DataContext="{Binding Source={StaticResource Locator},Path=BothWayBind}"
mc:Ignorable="d"
Title="BothWayBindView" Height="450" Width="800">
<Window.Resources>
View Code
实现INotifyPropertyChanged接口的基类
public abstract class ViewModelBase : INotifyPropertyChanged
public event PropertyChangedEventHandler PropertyChanged;
/// <summary>
/// Sets property if it does not equal existing value. Notifies listeners if change occurs.
/// </summary>
/// <typeparam name="T">Type of property.</typeparam>
/// <param name="member">The property's backing field.</param>
/// <param name="value">The new value.</param>
/// <param name="propertyName">Name of the property used to notify listeners. This
/// value is optional and can be provided automatically when invoked from compilers
/// that support <see cref="CallerMemberNameAttribute"/>.</param>
protected virtual bool SetProperty<T>(ref T member, T value, [CallerMemberName] string propertyName = null)
if (EqualityComparer<T>.Default.Equals(member, value))
return false;
member = value;
OnPropertyChanged(propertyName);
return true;
/// <summary>
/// Notifies listeners that a property value has changed.
/// </summary>
/// <param name="propertyName">Name of the property, used to notify listeners.</param>
protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
=> PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
View Code
model绑定
public class SelectableViewModel : ViewModelBase
private bool _isSelected;
private string _name;
private string _description;
private char _code;
private double _numeric;
private string _food;
private string _visibility;
public bool IsSelected
get => _isSelected;
set => SetProperty(ref _isSelected, value);
public string Visibility
get => _visibility;
set => SetProperty(ref _visibility, value);
public char Code
get => _code;
set => SetProperty(ref _code, value);
public string Name
get => _name;
set => SetProperty(ref _name, value);
public string Description
get => _description;
set => SetProperty(ref _description, value);
public double Numeric
get => _numeric;
set => SetProperty(ref _numeric, value);
public string Food
get => _food;
set => SetProperty(ref _food, value);
View Code
MVVMLight
调用MVVMLight的ObservableObject，自动实现INotifyPropertyChanged，在属性中添加 RaisePropertyChanged(() => “属性名”);
public class WelcomeModel : ObservableObject
private String introduction;
/// <summary>
/// 欢迎词
/// </summary>
public String Introduction
get { return introduction; }
introduction = value; RaisePropertyChanged(() => Introduction);
View Code
注意：对于数组集合类的，一定使用ObservableCollection声明(原生和MVVMLight两者都适用)
public ObservableCollection<MovieCategory> MovieCategories { get; }
MovieCategories = new ObservableCollection<MovieCategory>
new MovieCategory("一号货架",
new Movie("一排一号", "1001"),
new Movie("二排一号", "1002"),
new Movie("三排一号", "1003")),
new MovieCategory("二号货架",
new Movie("一排一号", "2001"),
new Movie("二排一号", "2002")
View Code
因为ObservableCollection实现了接口Collection<T>, INotifyCollectionChanged, INotifyPropertyChanged，而List没有实现INotifyCollectionChanged, INotifyPropertyChanged。
[TypeForwardedFrom("WindowsBase, Version=3.0.0.0, Culture=Neutral, PublicKeyToken=31bf3856ad364e35")]
public class ObservableCollection<T> : Collection<T>, INotifyCollectionChanged, INotifyPropertyChanged
public ObservableCollection();
// 摘要:
// Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection`1
// class that contains elements copied from the specified list.
// 参数:
// list:
// The list from which the elements are copied.
// 异常:
// T:System.ArgumentNullException:
// The list parameter cannot be null.
public ObservableCollection(List<T> list);
public ObservableCollection(IEnumerable<T> collection);
public event NotifyCollectionChangedEventHandler CollectionChanged;
protected event PropertyChangedEventHandler PropertyChanged;
public void Move(int oldIndex, int newIndex);
protected IDisposable BlockReentrancy();
protected void CheckReentrancy();
protected override void ClearItems();
protected override void InsertItem(int index, T item);
protected virtual void MoveItem(int oldIndex, int newIndex);
protected virtual void OnCollectionChanged(NotifyCollectionChangedEventArgs e);
protected virtual void OnPropertyChanged(PropertyChangedEventArgs e);
protected override void RemoveItem(int index);
protected override void SetItem(int index, T item);
View Code
实现ICommand接口
/// <summary>
/// No WPF project is complete without it's own version of this.
/// </summary>
public class AnotherCommandImplementation : ICommand
private readonly Action<object> _execute;
private readonly Func<object, bool> _canExecute;
public AnotherCommandImplementation(Action<object> execute)
: this(execute, null)
public AnotherCommandImplementation(Action<object> execute, Func<object, bool> canExecute)
if (execute is null) throw new ArgumentNullException(nameof(execute));
_execute = execute;
_canExecute = canExecute ?? (x => true);
public bool CanExecute(object parameter) => _canExecute(parameter);
public void Execute(object parameter) => _execute(parameter);
public event EventHandler CanExecuteChanged
CommandManager.RequerySuggested += value;
remove
CommandManager.RequerySuggested -= value;
public void Refresh() => CommandManager.InvalidateRequerySuggested();
View Code
public AnotherCommandImplementation AddCommand { get; }
public AnotherCommandImplementation RemoveSelectedItemCommand { get; }
AddCommand = new AnotherCommandImplementation(
if (!MovieCategories.Any())
MovieCategories.Add(new MovieCategory(GenerateString(15)));
var index = new Random().Next(0, MovieCategories.Count);
MovieCategories[index].Movies.Add(
new Movie(GenerateString(15), GenerateString(20)));
RemoveSelectedItemCommand = new AnotherCommandImplementation(
var movieCategory = SelectedItem as MovieCategory;
if (movieCategory != null)
MovieCategories.Remove(movieCategory);
var movie = SelectedItem as Movie;
if (movie == null) return;
MovieCategories.FirstOrDefault(v => v.Movies.Contains(movie))?.Movies.Remove(movie);
_ => SelectedItem != null);
View Code
MVVMLight
using GalaSoft.MvvmLight.CommandWpf;
using MVVMLightDemo.Model;
using System.Collections.ObjectModel;
namespace MVVMLightDemo.ViewModel
public class CommandViewModel:ViewModelBase
public CommandViewModel()
//构造函数
ValidateUI = new ValidateUserInfo();
List = new ObservableCollection<ValidateUserInfo>();
#region 全局属性
private ObservableCollection<ValidateUserInfo> list;
/// <summary>
/// 用户数据列表
/// </summary>
public ObservableCollection<ValidateUserInfo> List
get { return list; }
set { list = value; }
private ValidateUserInfo validateUI;
/// <summary>
/// 当前操作的用户信息
/// </summary>
public ValidateUserInfo ValidateUI
get { return validateUI; }
validateUI = value;
RaisePropertyChanged(() => ValidateUI);
#endregion
#region 全局命令
private RelayCommand submitCmd;
/// <summary>
/// 执行提交命令的方法
/// </summary>
public RelayCommand SubmitCmd
if (submitCmd == null) return new RelayCommand(() => ExcuteValidForm(),CanExcute);
return submitCmd;
set { submitCmd = value; }
#endregion
#region 附属方法
/// <summary>
/// 执行提交方法
/// </summary>
private void ExcuteValidForm()
List.Add(new ValidateUserInfo(){ UserEmail= ValidateUI.UserEmail, UserName = ValidateUI.UserName, UserPhone = ValidateUI.UserPhone });
/// <summary>
/// 是否可执行（这边用表单是否验证通过来判断命令是否执行）
/// </summary>
/// <returns></returns>
private bool CanExcute()
return ValidateUI.IsValidated;
#endregion
View Code
注意：CanExecuteChanged，CanExecute，Execute的说明
Messenger消息注册
如果需要某张视图页面弹出对话框、弹出子窗体、处理界面元素，播放动画等。如果这些操作都放在ViewModel中，就会导致ViewModel还是要去处理View级别的元素，造成View和ViewModel的依赖。
最好的办法就是ViewModel通知View应该做什么，而View监听接收到命令，并去处理这些界面需要处理的事情。
2、ViewModel和ViewModel之间也需要通过消息传递来完成一些交互。
而MVVM Light 的 Messenger类，提供了解决了上述两个问题的能力:
Messenger类用于应用程序的通信，接受者只能接受注册的消息类型，另外目标类型可以被指定，用Send<TMessage, TTarget>(TMessage message) 实现，
InitializeComponent();
//消息标志token：ViewAlert，用于标识只阅读某个或者某些Sender发送的消息，并执行相应的处理，所以Sender那边的token要保持一致
//执行方法Action：ShowReceiveInfo，用来执行接收到消息后的后续工作，注意这边是支持泛型能力的，所以传递参数很方便。
Messenger.Default.Register<String>(this, "ViewAlert", ShowReceiveInfo);
this.DataContext = new MessengerRegisterForVViewModel();
//卸载当前(this)对象注册的所有MVVMLight消息
this.Unloaded += (sender, e) => Messenger.Default.Unregister(this);
/// <summary>
/// 接收到消息后的后续工作：根据返回来的信息弹出消息框
/// </summary>
/// <param name="msg"></param>
private void ShowReceiveInfo(String msg)
MessageBox.Show(msg);
View Code
if (sendCommand == null)
sendCommand = new RelayCommand(() => ExcuteSendCommand());
return sendCommand;
set { sendCommand = value; }
private void ExcuteSendCommand()
Messenger.Default.Send<String>("ViewModel通知View弹出消息框", "ViewAlert"); //注意：token参数一致
#endregion
View Code
比如弹出框，可以在ViewMode中使用，但是需要引入using System.Windows;如果是子页面，就脱了了View和ViewModel解耦的初衷。
