QUOT&;吨GT&;新的EventHandler<采用QUOT接线事件与区别;并没有使用新的EventHandler< T>"？ [英] Difference between wiring events using "new EventHandler<T>" and not using new EventHandler<T>"?

问题描述

什么是两者之间的区别

object.ProgressChanged += new EventHandler<ProgressChangedEventArgs>(object_ProgressChanged)

object.ProgressChanged += object_ProgressChanged;

    void installableObject_InstallProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        EventHandler<ProgressChangedEventArgs> progress = ProgressChanged;
        if (installing != null)
            installing(this, e);
    }

编辑：

如果没有差异，这是更好的选择？

If there are no difference, which is the better choice?

谢谢！

推荐答案

基本上，一个是比另一个要短。这只是synctactic糖。

Basically, one is shorter than the other. It's just synctactic sugar.

正确的语法是第一位的，因为ProgresChanged是一个事件处理程序的事件，所以你到一个实际的处理器分配给它，你需要创建一个新的EventHandler对象，其构造函数作为参数与要求签名的方法的名称。

The "correct" syntax is the first one, as ProgresChanged is an EventHandler event, so for you to assign a actual handler to it, you need to create a new EventHandler object, whose constructor takes as a parameter the name of a method with the required signature.

不过，如果你只是指定方法的名称（第二个语法），该事件处理程序类的一个实例是隐式创建，该实例分配给ProgressChanged事件。

However, if you just specify the name of the method (second syntax), an instance of the eventHandler class is created implicitly, and that instance is assigned to the ProgressChanged event.

我更喜欢使用第二种方法，因为它是短，不会丢失任何信息。有没有太多的上下文，你会认错一个 + =方法名构建别的东西。

I prefer using the second method because it's shorter, and does not lose any information. There are not much contexts where you could mistake a += methodName construct for something else.

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