c# - 我有事件处理程序 (c#) 的问题

Question

这段代码来自一个类

 Button pagebtn = new Button();
 pagebtn.Text = "2";

 pagebtn.Click += 
        listTopicPerPage_Click(this, new btnEventArgs() { btnNumber = 2 });

我在 eventHandler 方法上加了一条下划线，说..

cannot immplicitly convert type 'void' to 'System.EventHandler'.

这是为什么？

我创建的另一个类的代码:

class btnEventArgs : EventArgs
{
    public int btnNumber { get; set; }
}

Answer 1

要指定事件参数，您应该在类中创建一个事件字段，并根据需要将其提升:

public partial class WebForm1 : System.Web.UI.Page
{
    public event EventHandler<btnEventArgs> SampleEvent;

    public void DemoEvent(int val)
    {
        // Copy to a temporary variable to be thread-safe.
        EventHandler<btnEventArgs> temp = SampleEvent;
        if (temp != null)
            temp(this, new btnEventArgs { btnNumber = val });
    }


    protected void Page_Load(object sender, EventArgs e)
    {
        Button1.Click += new EventHandler(Button1_Click);
    }

    void Button1_Click(object sender, EventArgs e)
    {
        DemoEvent(2);
    }
}

class btnEventArgs : EventArgs 
{
    public int btnNumber { get; set; } 
}

MSDN article