C#中异步回调函数用法实例

本文实例讲述了c#中异步回调函数用法。分享给大家供大家参考。具体如下：

static void main(string[] args)
{
 func<string,string> showmessage = showmessage;
 //设置了回调函数completed,不能有返回值
 iasyncresult result = showmessage.begininvoke("测试异步委托",new asynccallback(completed),null);
 //半段异步是否结束
 while(!result.iscompleted)
 {
  console.writeline("主线程可以进行其它的操作！");
 }
 console.readline();
}
static string showmessage(string x)
{
 string current = string.format("当前线程id为{0}",thread.currentthread.managedthreadid);
 thread.sleep(3000);
 return string.format("{0},输入为{1}", current, x);
}
static void completed(iasyncresult result)
{
 console.writeline("异步完成！");
 //获取委托对象，并用endinvoke方法获取返回结果
 asyncresult _result = (asyncresult) result;
 func<string, string> showmessage = (func<string, string>) _result.asyncdelegate;
 //结束异步操作并输出
 console.writeline(showmessage.endinvoke(_result));
}

希望本文所述对大家的c#程序设计有所帮助。