MVVMLight leaning note

Learning Note For MvvmLight

MvvmLight quitstart

refer link1 : MVVMLight HelloWorld

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mc:Ignorable usage.

we have a lot of places using mc:Ignorable in our xaml. it is used to Comment code in xaml.how to use it in our xaml, we can refer this topic.

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SimpleIOC

ViewModelLocator.cs Analysis

1. when we use mvvmlight template, we will have a file called ViewModelLocator.cs General Structor here:

   using GalaSoft.MvvmLight;
   
   using GalaSoft.MvvmLight.Ioc;
   
   using Microsoft.Practices.ServiceLocation;

   namespace mvvmtemplate.ViewModel
   
   {
   
   ///
   

   
   
   /// This class contains static references to all the view models in the
   
   /// application and provides an entry point for the bindings.
   
   ///

   public class ViewModelLocator
   
   {
   
   ///
   

   
   
   /// Initializes a new instance of the ViewModelLocator class.
   
   ///

   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>();
        }
   
        public MainViewModel Main
        {
            get
            {
                return ServiceLocator.Current.GetInstance<MainViewModel>();
            }
        }
   
        public static void Cleanup()
        {
            // TODO Clear the ViewModels
        }
    }
   

   }

three key point: ServiceLocator.SetLocatorProvider(()=>SimpleIoc.Default) SimpleIoc.Default.Register() ServiceLocator.Current.GetInstance()

1. for usage of SimpleIoc.Default.Register<>(), we can see the dll of the MvvmLight, a lot of overload functions about this. It is used to register the class to the SimpleIoc. Note: T class should only have one Contructor function, otherwise, it will report a error.

2. ServiceLocator.Current.GetInstance(), it is used to get a instance of the Class T. it is used to for singleInstance mode, other overload functions definited in dll.

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Messager

it is used to send specified message between MVVM. Simple usage.

1. Register a specified message to an object.
   
   Sample code:

   Messenger.Default.Register(object, Action);

Summary:

Registers a recipient for a type of message TMessage. The action parameter will be executed when a corresponding message is sent.

Registering a recipient does not create a hard reference to it, so if this recipient is deleted, no memory leak is caused.

1. Send a specified message.
   
   Sample code:

   public virtual void Send(TMessage message){}

Summary:

Sends a message to registered recipients. The message will reach all recipients that registered for this message type using one of the Register methods.

Type Parameters:

TMessage: The type of message that will be sent.

Parameters:

message: The message to send to registered recipients.

How to use:

Messenger.Default.Send(new TMessage(s));