MVVM:如何将参数传递给ViewModel的构造函数

Question

我正在使用L. Bugnion的MVVM Light Framework.
将客户ID等参数传递给ViewModel构造函数的一些推荐方法是什么？

编辑:每个ViewModel所需的参数不是跨模型共享的参数.它是每个viewmodel实例独有的东西.

Answer 1

//Create a container class to pass via messenger service
    public class CarSelectedArgs
    {
      #region Declarations

      public Car Car { get; set; }

      #endregion

      #region Constructor

      public CarSelectedArgs(Car car)
      {
        Car = car;
      }

      #endregion
    }


    //example of view model sending message.
    public class SendingViewModel : ViewModelBase
    {
      private Car _car;
      public Car SelectedCar
      {
        get { return _car; }
        set
        {
          _car = value;
          if (value != null)
          {
            //messenger will notify all classes that have registered for a message of this type
            Messenger.Default.Send(new CarSelectedArgs(value));
          }
        }
      }
    }


    //Example of ViewModel registering to recieve a message
    public class SampleViewModel : ViewModelBase
    {
      #region Constructor

      public SampleViewModel()
      {
        Messenger.Default.Register<CarSelectedArgs>(this, OnCarSelected);
      }
      #endregion

      #region LocalMethods

      void OnCarSelected(CarSelectedArgs e)
      {

        var NewCar = e.Car;
      }

      #endregion
    }

Answer 2

使用接口通过注入请求任何你想要的东西。

如果您有跨模型共享的设置，请实例化包含值的单例并通过ISomethingProvider和ISomethingEditor接口公开它们。