C# - 为什么使用 EventHandler 会出错？

Question

做一个 Pluralsight 视频，但不知道为什么会出错。
关于这一点的错误消息:

worker.WorkPerformed += new EventHandler<WorkPerformedEventArgs>(worker_WorkPerformed);

错误消息:

Cannot implicity convert to type'System.EventHandler<AB_Events.WorkPerformedEventArgs>' to'AB_Events.WorkPerformedHandler'

片段

public delegate int WorkPerformedHandler(object sender,WorkPerformedEventArgs e);
public class Worker
{
    public event WorkPerformedHandler WorkPerformed;
    protected virtual void OnWorkPerformed(int hours, WorkType workType)
    {  
        var del = WorkPerformed as WorkPerformedHandler;
        if (del != null)
        {
            del(this, new WorkPerformedEventArgs(hours, workType));
        }
    }
}

和

class Program
{
    static void Main(string[] args)
    {
        var worker = new Worker();

        worker.WorkPerformed += new EventHandler<WorkPerformedEventArgs>(worker_WorkPerformed);

        Console.ReadKey();
    }

    public static void worker_WorkPerformed(object sender, WorkPerformedEventArgs e)
    {
        throw new NotImplementedException();
    }
}

Answer 1

我所做的是替换WorkPerformedHandler来自 EventHandler<WorkPerformedEventArgs>

public delegate int WorkPerformedHandler(object sender, WorkPerformedEventArgs e);
public class Worker
{
    public event EventHandler<WorkPerformedEventArgs> WorkPerformed;
    protected virtual void OnWorkPerformed(WorkPerformedEventArgs e)
    {
        WorkPerformed?.Invoke(this, e);
    }
}

事件订阅:

var worker = new Worker();
worker.WorkPerformed += new EventHandler<WorkPerformedEventArgs>(worker_WorkPerformed);