C#中进程的挂起与恢复

程序员文章站 2023-11-25 15:34:28

1. 源起：仍然是模块化编程所引发的需求。产品经理难伺候，女产品经理更甚之~:p 纯属戏谑，技术方案与产品经理无关，芋头莫怪！ vcu10项目重构，要求各功能模块以...

1. 源起：

仍然是模块化编程所引发的需求。产品经理难伺候，女产品经理更甚之~:p

纯属戏谑，技术方案与产品经理无关，芋头莫怪！

vcu10项目重构，要求各功能模块以独立进程方式实现，比如：音视频转换模块，若以独立进程方式实现，如何控制其暂停、继续等功能呢？

线程可以suspend、resume，c#内置的process没有此类方法，咋整？

山穷水尽疑无路，柳暗花明又一村。情到浓时清转薄，此情可待成追忆！

前篇描述了进程间数据传递方法，此篇亦以示例演示其间控制与数据交互方法。

2、未公开的api函数：ntsuspendprocess、ntresumeprocess

此类函数在msdn中找不到。

思其原因，概因它们介于windows api和内核api之间，威力不容小觑。怕二八耙子程序员滥用而引发事端，因此密藏。

其实还有个ntterminateprocess，因process有kill方法，因此可不用。

但再隐秘的东西，只要有价值，都会被人给翻出来，好酒不怕巷子深么！

好，基于其，设计一个进程管理类，实现模块化编程之进程间控制这个需求。

3、processmgr

直上代码吧，封装一个进程管理单元：

public static class processmgr
 {
  /// <summary>
  /// the process-specific access rights.
  /// </summary>
  [flags]
  public enum processaccess : uint
  {
   /// <summary>
   /// required to terminate a process using terminateprocess.
   /// </summary>
   terminate = 0x1,
   /// <summary>
   /// required to create a thread.
   /// </summary>
   createthread = 0x2,
   /// <summary>
   /// undocumented.
   /// </summary>
   setsessionid = 0x4,
   /// <summary>
   /// required to perform an operation on the address space of a process (see virtualprotectex and writeprocessmemory).
   /// </summary>
   vmoperation = 0x8,
   /// <summary>
   /// required to read memory in a process using readprocessmemory.
   /// </summary>
   vmread = 0x10,
   /// <summary>
   /// required to write to memory in a process using writeprocessmemory.
   /// </summary>
   vmwrite = 0x20,
   /// <summary>
   /// required to duplicate a handle using duplicatehandle.
   /// </summary>
   duphandle = 0x40,
   /// <summary>
   /// required to create a process.
   /// </summary>
   createprocess = 0x80,
   /// <summary>
   /// required to set memory limits using setprocessworkingsetsize.
   /// </summary>
   setquota = 0x100,
   /// <summary>
   /// required to set certain information about a process, such as its priority class (see setpriorityclass).
   /// </summary>
   setinformation = 0x200,
   /// <summary>
   /// required to retrieve certain information about a process, such as its token, exit code, and priority class (see openprocesstoken, getexitcodeprocess, getpriorityclass, and isprocessinjob).
   /// </summary>
   queryinformation = 0x400,
   /// <summary>
   /// undocumented.
   /// </summary>
   setport = 0x800,
   /// <summary>
   /// required to suspend or resume a process.
   /// </summary>
   suspendresume = 0x800,
   /// <summary>
   /// required to retrieve certain information about a process (see queryfullprocessimagename). a handle that has the process_query_information access right is automatically granted process_query_limited_information.
   /// </summary>
   querylimitedinformation = 0x1000,
   /// <summary>
   /// required to wait for the process to terminate using the wait functions.
   /// </summary>
   synchronize = 0x100000
  }
  [dllimport("ntdll.dll")]
  private static extern uint ntresumeprocess([in] intptr processhandle);
  [dllimport("ntdll.dll")]
  private static extern uint ntsuspendprocess([in] intptr processhandle);
  [dllimport("kernel32.dll", setlasterror = true)]
  private static extern intptr openprocess(
   processaccess desiredaccess,
   bool inherithandle,
   int processid);
  [dllimport("kernel32.dll", setlasterror = true)]
  [return: marshalas(unmanagedtype.bool)]
  private static extern bool closehandle([in] intptr handle);
  public static void suspendprocess(int processid)
  {
   intptr hproc = intptr.zero;
   try
   {
    // gets the handle to the process
    hproc = openprocess(processaccess.suspendresume, false, processid);
    if (hproc != intptr.zero)
     ntsuspendprocess(hproc);
   }
   finally
   {
    // don't forget to close handle you created.
    if (hproc != intptr.zero)
     closehandle(hproc);
   }
  }
  public static void resumeprocess(int processid)
  {
   intptr hproc = intptr.zero;
   try
   {
    // gets the handle to the process
    hproc = openprocess(processaccess.suspendresume, false, processid);
    if (hproc != intptr.zero)
     ntresumeprocess(hproc);
   }
   finally
   {
    // don't forget to close handle you created.
    if (hproc != intptr.zero)
     closehandle(hproc);
   }
  }
 }

4、进程控制

我权且主进程为宿主，它通过process类调用子进程，得其id，以此为用。其调用代码为：

 private void runtestprocess(bool hidden = false)
  {
   string apppath = path.getdirectoryname(application.executablepath);
   string testapppath = path.combine(apppath, "testapp.exe");
   var pi = new processstartinfo();
   pi.filename = testapppath;
   pi.arguments = this.handle.tostring();
   pi.windowstyle = hidden ? processwindowstyle.hidden : processwindowstyle.normal;
   this.childprocess = process.start(pi);
   txtinfo.text = string.format("子进程id：{0}\r\n子进程名：{1}", childprocess.id, childprocess.processname);
   ...
  }

控制代码为：

private void btnwork_click(object sender, eventargs e)
  {
   if (this.childprocess == null || this.childprocess.hasexited)
    return;
   if ((int)btnwork.tag == 0)
   {
    btnwork.tag = 1;
    btnwork.text = "恢复";
    processmgr.suspendprocess(this.childprocess.id);
   }
   else
   {
    btnwork.tag = 0;
    btnwork.text = "挂起";
    processmgr.resumeprocess(this.childprocess.id);
   }
  }

子进程以一定时器模拟其工作，向主进程抛进度消息：

 private void timer_tick(object sender, eventargs e)
  {
   if (progressbar.value < progressbar.maximum)
    progressbar.value += 1;
   else
    progressbar.value = 0;
   if (this.hosthandle != intptr.zero)
    sendmessage(this.hosthandle, wm_progress, 0, progressbar.value);
  }

代码量就这么的少，简单吧……

5、效果图：

为示例，做了两个图，其一为显示子进程，其二为隐藏子进程。

C#中进程的挂起与恢复