Caliburn笔记-Presenter(wpf框架)

    又是MVP...

先来看下图,MetadataContainer已经知道是元数据的功能了。PresenterBase继承了IExtendedPresenter接口,所以重点看这个接口.

参考于此:http://caliburn.codeplex.com/wikipage?title=IPresenter%20Component%20Model&referringTitle=Documentation

IExtendedPresenter接口继承了一系列的接口

IPresenter包含了一组基本初始化的方法

IPresenterNode

IPresenterNode inherits from IPresenter and adds one additional property: Parent. This allows the implementor to communicate directly with its immediate parent. This is most helpful in shutdown scenarios. An example of this can be seen by examining the PresenterBase.Close method.

ILifecycleNotifier

Classes which implement this interface guarantee that they will fire events related to their lifecycle. These events correspond directly to the methods defined by IPresenter. The events are: Initialized, WasShutdown, Activated, Deactivated.

IViewAware

This interface should be implemented when explicit knowledge of the view is needed. If implemented, when the view's Loaded event is fired, the IViewWare.ViewLoaded method will be called. It will be passed the view instance and the context that the view pertains to (because it is possible to have multiple view over the same model).

IPresenterHost

This interface inherits from IPresenter and is implemented by classes which which to manage the lifecycle of other presenter(s). This basically encompasses the ScreenConductor and ScreenCollection roles. The IPresenterHost has a collection of the IPresenters which it is managing called "Presenters" It also adds two important methods:

 

以下为PresenterBase抽象类代码

1.定义IPresenter抽象方法

#region abstract method

/// <summary>
/// Initializes this instance.
/// </summary>
public abstract void Initialize();

/// <summary>
/// Shuts down this instance.
/// </summary>
public abstract void Shutdown();

/// <summary>
/// Activates this instance.
/// </summary>
public abstract void Activate();

/// <summary>
/// Deactivates this instance.
/// </summary>
public abstract void Deactivate();

#endregion

2.定义ILifecycleNotifier接口事件

#region Event

/// <summary>
/// Occurs when [initialized].
/// </summary>
public event EventHandler Initialized = delegate { };

/// <summary>
/// Occurs when [was shutdown].
/// </summary>
public event EventHandler WasShutdown = delegate { };

/// <summary>
/// Occurs when [activated].
/// </summary>
public event EventHandler Activated = delegate { };

/// <summary>
/// Occurs when [deactivated].
/// </summary>
public event EventHandler Deactivated = delegate { };

/// <summary>
/// Called when [initialize].
/// </summary>
protected virtual void OnInitialize()
{
    Initialized(this, EventArgs.Empty);
}

/// <summary>
/// Called when [shutdown].
/// </summary>
protected virtual void OnShutdown()
{
    WasShutdown(this, EventArgs.Empty);
}

/// <summary>
/// Called when [activate].
/// </summary>
protected virtual void OnActivate()
{
    Activated(this, EventArgs.Empty);
}

/// <summary>
/// Called when [deactivate].
/// </summary>
protected virtual void OnDeactivate()
{
    Deactivated(this, EventArgs.Empty);
}

#endregion

3.IViewAware接口

/// <summary>
/// Called when the presenter's view is loaded.
/// </summary>
/// <param name="view">The view.</param>
/// <param name="context">The context.</param>
public virtual void ViewLoaded(object view, object context) {}

Presenter为PresenterBase默认实现

/// <summary>
    /// A base implementation of <see cref="IPresenter"/>.
    /// </summary>
    public class Presenter : PresenterBase
    {
        /// <summary>
        /// Initializes this instance.
        /// </summary>
        public override void Initialize()
        {
            if(!IsInitialized)
            {
                OnInitialize();
                IsInitialized = true;
            }
        }

        /// <summary>
        /// Shutdowns this instance.
        /// </summary>
        public override void Shutdown()
        {
            OnShutdown();
        }

        /// <summary>
        /// Activates this instance.
        /// </summary>
        public override void Activate()
        {
            if(!IsActive)
            {
                OnActivate();
                IsActive = true;
            }
        }

        /// <summary>
        /// Deactivates this instance.
        /// </summary>
        public override void Deactivate()
        {
            if(IsActive)
            {
                OnDeactivate();
                IsActive = false;
            }
        }
    }

到此为止,Presenter本身定义了方法与事件,但并不参与生命流程的制定.