1. 源起：
仍然是模塊化編程所引發的需求。產品經理難伺候，女產品經理更甚之~:p
純屬戲謔，技術方案與產品經理無關，芋頭莫怪！
vcu10項目重構，要求各功能模塊以獨立進程方式實現，比如：音視頻轉換模塊，若以獨立進程方式實現，如何控制其暫停、繼續等功能呢？
線程可以suspend、resume，c#內置的process沒有此類方法，咋整？
山窮水盡疑無路，柳暗花明又一村。情到濃時清轉薄，此情可待成追憶！
前篇描述了進程間數據傳遞方法，此篇亦以示例演示其間控制與數據交互方法。
2、未公開的api函數：ntsuspendprocess、ntresumeprocess
此類函數在msdn中找不到。
思其原因，概因它們介于windows api和 內核api之間，威力不容小覷。怕二八耙子程序員濫用而引發事端，因此密藏。
其實還有個ntterminateprocess，因process有kill方法，因此可不用。
但再隱秘的東西，只要有價值，都會被人給翻出來，好酒不怕巷子深么！
好，基于其，設計一個進程管理類，實現模塊化編程之進程間控制這個需求。
3、processmgr
直上代碼吧，封裝一個進程管理單元：
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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、進程控制
我權且主進程為宿主，它通過process類調用子進程，得其id，以此為用。其調用代碼為：
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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("子進程id：{0}\r\n子進程名：{1}", childprocess.id, childprocess.processname); ... } |
控制代碼為：
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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 = "恢復"; processmgr.suspendprocess(this.childprocess.id); } else { btnwork.tag = 0; btnwork.text = "掛起"; processmgr.resumeprocess(this.childprocess.id); } } |
子進程以一定時器模擬其工作，向主進程拋進度消息：
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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); } |
代碼量就這么的少，簡單吧……
5、效果圖：
為示例，做了兩個圖，其一為顯示子進程，其二為隱藏子進程。
實際項目調用獨立進程模塊，是以隱藏方式調用的，以宿主展示其處理進度，如此圖：
后記：
擴展思路，一些優秀的開源工具，如youtube_dl、ffmpeg等，都以獨立進程方式存在，且可通過cmd管理通信。
以此進程控制原理，可以基于這些開源工具，做出相當不錯的gui工具出來。畢竟相對于強大的命令行，人們還是以簡單操作為方便。
原文鏈接：http://www.cnblogs.com/crwy/p/6622319.html
