转自：https://hovertree.com/h/bjag/4dmf8x0u.htm
public delegate void OperateSuccessHanlder(string fileName); //创建委托
public event OperateSuccessHanlder OperateSuccess;
//UCPictureAdd.ascx.cs中的代码
void OnOperateSuccess(string fileName)
{
OperateSuccess?.Invoke(fileName);
}
上面代码等价于：
public delegate void OperateSuccessHanlder(string fileName); //创建委托
public event OperateSuccessHanlder OperateSuccess;
//UCPictureAdd.ascx.cs中的代码
void OnOperateSuccess(string fileName)
{
if(OperateSuccess!=null)
{
OperateSuccess(fileName);
}
}
原文：https://www.cnblogs.com/baozi789654/p/14842709.html