C#异步调用实例小结

本文实例讲述了c#异步调用的方法。分享给大家供大家参考。具体如下：

using system;
using system.collections.generic;
using system.componentmodel;
using system.data;
using system.drawing;
using system.text;
using system.threading;
using system.windows.forms;
namespace cw
{
 public partial class asyncdemo : form
 {
  public asyncdemo()
  {
   initializecomponent();
  }
  private void delgate_load(object sender, eventargs e)
  {
  }
  /// <summary>
  /// 实现委托的方法
  /// </summary>
  /// <param name="icalltime"></param>
  /// <param name="iexecthread"></param>
  /// <returns></returns>
  string longrunningmethod(int icalltime, out int iexecthread)
  {
   thread.sleep(icalltime);
   iexecthread = appdomain.getcurrentthreadid();
   return "mycalltime was " + icalltime.tostring();
  }
  delegate string methoddelegate(int icalltime, out int iexecthread);
  #region 示例 1： 同步调用方法#region 示例 1： 同步调用方法
  /// <summary>
  /// 示例 1： 同步调用方法
  /// </summary>
  public void demosynccall()
  {
   string s;
   int iexecthread;
   // create an instance of a delegate that wraps longrunningmethod.
   methoddelegate dlgt = new methoddelegate(this.longrunningmethod);
   // call longrunningmethod using the delegate.
   s = dlgt(3000, out iexecthread);
   messagebox.show(string.format ("the delegate call returned the string: {0}, and the thread id {1}", s, iexecthread.tostring() ) );
  }
  #endregion
  #region 示例 2： 通过 endinvoke() 调用模式异步调用方法
  /// <summary>
  /// 示例 2： 通过 endinvoke() 调用模式异步调用方法  
  /// </summary>
  public void demoendinvoke()
  {
   methoddelegate dlgt = new methoddelegate(this.longrunningmethod);
   string s;
   int iexecthread;
   // initiate the asynchronous call.
   iasyncresult ar = dlgt.begininvoke(5000, out iexecthread, null, null);
   // do some useful work here. this would be work you want to have
   // run at the same time as the asynchronous call.
   // retrieve the results of the asynchronous call.
   s = dlgt.endinvoke(out iexecthread, ar);
   messagebox.show(string.format ("the delegate call returned the string: {0}, and the number {1}", s, iexecthread.tostring() ) );
  }
  #endregion
  #region 示例 3： 异步调用方法并使用 a waithandle 来等待调用完成
  /// <summary>
  /// 示例 3： 异步调用方法并使用 a waithandle 来等待调用完成
  /// </summary>
  public void demowaithandle()
  {
   string s;
   int iexecthread;
   methoddelegate dlgt = new methoddelegate(this.longrunningmethod);
   // initiate the asynchronous call.
   iasyncresult ar = dlgt.begininvoke(3000, out iexecthread, null, null);
   // do some useful work here. this would be work you want to have
   // run at the same time as the asynchronous call.
   // wait for the waithandle to become signaled.
   ar.asyncwaithandle.waitone();
   // get the results of the asynchronous call.
   s = dlgt.endinvoke(out iexecthread, ar);
   messagebox.show(string.format ("the delegate call returned the string: {0}, and the number {1}", s, iexecthread.tostring() ) );
  }
  #endregion
  #region 示例 4： 异步调用方法通过轮询调用模式
  /// <summary>
  /// 示例 4： 异步调用方法通过轮询调用模式
  /// </summary>
  public void demopolling()
  {
   methoddelegate dlgt = new methoddelegate(this.longrunningmethod);
   string s;
   int iexecthread;
   // initiate the asynchronous call.
   iasyncresult ar = dlgt.begininvoke(3000, out iexecthread, null, null);
   // poll iasyncresult.iscompleted
   while (ar.iscompleted == false)
   {
    thread.sleep(10); // pretend to so some useful work
   }
   s = dlgt.endinvoke(out iexecthread, ar);
   messagebox.show(string.format ("the delegate call returned the string: {0}, and the number {1}", s, iexecthread.tostring() ) );
  }
  #endregion
  #region 示例 5： 异步方法完成后执行回调
  /// <summary>
  /// 示例 5： 异步方法完成后执行回调
  /// </summary>
  public void democallback()
  {
   methoddelegate dlgt = new methoddelegate(this.longrunningmethod);
   int iexecthread;
   // create the callback delegate.
   asynccallback cb = new asynccallback(myasynccallback);
   // initiate the asynchronous call passing in the callback delegate
   // and the delegate object used to initiate the call.
   iasyncresult ar = dlgt.begininvoke(5000, out iexecthread, cb, dlgt);
  }
  public void myasynccallback(iasyncresult ar)
  {
   string s;
   int iexecthread;
   // because you passed your original delegate in the asyncstate parameter
   // of the begin call, you can get it back here to complete the call.
   methoddelegate dlgt = (methoddelegate)ar.asyncstate;
   // complete the call.
   s = dlgt.endinvoke(out iexecthread, ar);
   messagebox.show(string.format("the delegate call returned the string: {0}, and the number {1}", s, iexecthread.tostring()));
   //console.writeline(string.format ("the delegate call returned the string: "{0}", and the number {1}", s, iexecthread.tostring() ) );
  }
  #endregion
  private void button1_click(object sender, eventargs e)
  {
   //demosynccall() ;
   //demoendinvoke();
   //demowaithandle();
   //demopolling();
   democallback();
  }
 }
}

希望本文所述对大家的c#程序设计有所帮助。