如何在MVVM中使用命令 [英] How to use Commands in MVVM

问题描述

我的模特：

my model :

class Login
    {
        public string Name{ get; set; }
        public string Password { get; set; }
    }

我的视图模型：

my view model :

class LoginViewModel : ObservableObject, INotifyPropertyChanged, ICommand
   {
       class LoginViewModel
       {
           Models.Login _mylogin = new Models.Login();
       }
   }

private readonly Models.Login _mylogin;
        public string Name
        {
            get { return _mylogin.Name; }
            set { _mylogin.Name= value; NotifyPropertyChanged("Name"); }
        }
        public string Password
        {
            get { return _mylogin.Password; }
            set { _mylogin.Password = value; NotifyPropertyChanged("Password"); }
        }

public event PropertyChangedEventHandler PropertyChanged;
       protected void NotifyPropertyChanged(string info)
       {
           if (PropertyChanged != null)
           {
               PropertyChanged(this, new PropertyChangedEventArgs(info));
           }
       }

问题：实施最简单的方法是什么icommand？ 。这是我第一个使用MVVM patern的wpf示例。我想知道命令是如何工作的。（对不起我的英语不好）

Question: What is the easiest way to implement icommand ? . this is my first wpf example with MVVM patern . i would like to know how command works.(sorry for my poor english)

推荐答案

对MVVM的一些好的支持可以在Josh Smith的MVVM Foundation库 [ ^ ]。

有一个 RelayCommand 的实现和其他非常有用的东西！

Some good support for MVVM can be found in Josh Smith's MVVM Foundation library[^].
There is an implementation of RelayCommand and other quite useful stuff!

你绝对是应该做更多的阅读。但是为了让你开始......



你不希望你的VM实现ICommand。命令是VM公开的单独对象。为避免为每个命令创建一个类，使用名为DelegateCommand或RelayCommand的通用实现。您可以自己实现一个或使用一个MVVM框架（例如Prism，此处提供更多链接）。作为name表明该命令会将调用转发给您在构造函数中提供的委托。以下是它的工作原理：

You definitely should do more reading. But to get you started...

You don't want your VM to implement ICommand. Commands are separate objects exposed by your VM. To avoid creating a class for each command a common implementation named DelegateCommand or RelayCommand is used. You can implement one yourself or use one which comes with a MVVM framework (e.g. Prism, some more links here). As the name suggest the command will relay the call to a delegate you provide in the constructor. Here is how it works:

class LoginViewModel 
{
  ICommand MyCommand { get; private set; }

  public LoginViewModel()
  {
    MyCommand = new DelegateCommand(MyMethod);
  }

  private void MyMethod(object parameter)
  {
    // handle the call here
  }
}

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