如何在c#中订阅其他类的事件？

Question

一个简单的场景:一个引发事件的自定义类.我希望在表单中使用此事件并对其做出反应.我怎么做？代码示例,请!

请注意,表单和自定义类是单独的类.

Answer 1

public class EventThrower
{
    public delegate void EventHandler(object sender, EventArgs args) ;
    public event EventHandler ThrowEvent = delegate{};

    public void SomethingHappened() => ThrowEvent(this, new EventArgs());
}

public class EventSubscriber
{
    private EventThrower _Thrower;

    public EventSubscriber()
    {
        _Thrower = new EventThrower();
        // using lambda expression..could use method like other answers on here

        _Thrower.ThrowEvent += (sender, args) => { DoSomething(); };
    }

    private void DoSomething()
    {
       // Handle event.....
    }
}

Answer 2

在你的表格内:

private void SubscribeToEvent(OtherClass theInstance) => theInstance.SomeEvent += this.MyEventHandler;

private void MyEventHandler(object sender, EventArgs args)
{
    // Do something on the event
}

您只需按照与表单中的事件相同的方式订阅其他类上的事件.要记住的三件重要事情:

1)您需要确保您的方法(事件处理程序)具有适当的声明以匹配另一个类上的事件的委托类型.

2)您需要看到其他课程的事件(即:公共或内部).

3)订阅类的有效实例,而不是类本身.