Question

我有两堂课。在一堂课中，我创建并引发了一个事件，如下所示：

CustomerAdd类

public class CustomerAdd
{
public delegate void Done(object Sender, EventArgs e);
public event Done ListUpdated;

public void UpdateNewList()
{
 //adding items to a generic List<T>,code removed as not relevant to post
 //and raising the event afterwards

 if (ListUpdated != null)
 {
  ListUpdated(this, EventArgs.Empty);
 }
}
}

MyWindow类

public class MyWindow
{
private void SaveToDisk()
 {
  CustomerAdd cuss = new CustomerAdd();
  cuss.ListUpdated += new CustomerAdd.Done(DisplayDetails);
  cuss.UpdateNewList();
 }
 private void DisplayDetails()
 {
  //other codes here
 }
}

现在，当我从SaveToDisk类调用MyWIndow方法时（由于我正在向DisplayDetails事件订阅ListUpDated方法），DisplayDetails为不叫。调试器显示ListUpdated为空。我已经搜索了几个小时，但未能提出解决方案。我关注了this link，但ListUpdated仍然为空。任何指导/帮助将不胜感激。

Answer 1

尝试一下：

using System;

namespace ConsoleApp1
{
    class Program
    {

        static void Main(string[] args)
        {
            CustomerReceive cr = new CustomerReceive();
            cr.SaveToDisk();

        }
    }

    public class CustomerAdd
    {
        public delegate void Done(object Sender, EventArgs e);
        public event Done ListUpdated;

        public void UpdateNewList()
        {
            //adding items to a generic List<T>,code removed as not relevant to post
            //and raising the event afterwards

            if (ListUpdated != null)
            {
                ListUpdated.Invoke(this, EventArgs.Empty);
            }
        }
    }

    public class CustomerReceive
    {
        public void SaveToDisk()
        {
            CustomerAdd cuss = new CustomerAdd();
            cuss.ListUpdated += new CustomerAdd.Done(DisplayDetails);
            cuss.UpdateNewList();
        }
        private void DisplayDetails(object Sender, EventArgs e)
        {
            int k = 0;
        }
    }
}

您需要对委托和事件进行良好的阅读，因为当有更多的侦听器时，这将不起作用

Answer 2

有效：

 $("#contractor").change(function() {
  $(this).val() === 'addnewcon'
  $('#addnewcon').modal({
    show: true
  });
});

C＃EventHandler在调用时返回null

2 个答案: