C#如何实现子进程跟随主进程关闭
目录
- 前言
- 一、如何实现
- 1、创建作业对象
- 2、子进程加入作业对象
- 3、销毁作业对象
- 二、完整代码
- 三、使用示例
- .net8.0
- 2、异常退出自动结束子进程
- 总结
前言
多进程开发经常会遇到主进程关闭,子进程需要跟随主进程一同关闭。比如调ffmpeg命令行实现的录屏程序,录屏程序关闭,ffmpeg进程也需要退出。我们通常在程序关闭时调用Process.Kill()杀掉fmpeg进程即可。但是如果是强制或异常关闭录屏程序,ffmpeg将会变成僵尸进程残留在系统中。本文将提供一种解决此类问题的方法。
一、如何实现
1、创建作业对象
(1)、创建对象
handle = CreateJobObject(IntPtr.Zero, null);
(2)、设置销毁作业时,关闭拥有的进程
var info = new JOBOBJECT_BASIC_LIMIT_INFORMATION { LimitFlags = 0x2000 }; var extendedInfo = new JOBOBJECT_EXTENDED_LIMIT_INFORMATION { php BasicLimitInformation = info }; int length = Marshal.SizeOf(typeof(JOBOBJECT_EXTENDED_LIMIT_INFORMATION)); IntPtr extendedInfoPtr = Marshal.AllocHGlobal(length); Marshal.StructureToPtr(extendedInfo, extendedInfoPtr, false); if (!SetInformationJoandroidbObject(handle, JobObjectInfoType.ExtendedLimitInformation, extendedInfoPtr, (uint)length)) throw new Exception(string.Format("Unable to set information. Error: {0}", Marshal.GetLastWin32Error()));
2、子进程加入作业对象
AssignProcessToJobObject(handle, processHandle);
3、销毁作业对象
(1)、手动销毁
CloseHandle(handle);
(2)、所在进程结束自动销毁
二、完整代码
using System.Diagnostics; using System.Runtime.InteropServices; namespace JobManagement { #region Helper classes /// <summary> /// 作业对象,主要用于子进程管理。 /// 目前版本是只支持作业销毁拥有的子进程退出 /// 通常可以定义一个全局静态变量使用 /// </summary> public class Job : IDisposable { [DllImport("kernel32.dll", CharSet = CharSet.Unicode)] static extern IntPtr CreateJobObject(IntPtr a, string lpName); [DllImport("kernel32.dll")] static extern bool SetInformationJobObject(IntPtr hJob, JobObjectInfoType infoType, IntPtr lpJobObjectInfo, UInt32 cbJobObjectInfoLength); [DllImport("kernel32.dll", SetLastError = true)] static extern bool AssignProcessToJobObject(IntPtr job, IntPtr process); [DllImport("kernel32.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] static extern bool CloseHandle(IntPtr hObject); private IntPtr handle; private bool disposed; public Job() { handle = CreateJobObject(IntPtr.Zero, null); var info = new JOBOBJECT_BASIC_LIMIT_INFORMATION { LimitFlandroidags = 0x2000 }; var extendedInfo = new JOBOBJECT_EXTENDED_LIMIT_INFORMATION { BasicLimitInformation = info }; int length = Marshal.SizeOf(typeof(JOBOBJECT_EXTENDED_LIMIT_INFORMATION)); IntPtr extendedInfoPtr = Marshal.AllocHGlobal(length); Marshal.StructureTo编程客栈Ptr(extendedInfo, extendedInfoPtr, false); if (!SetInformationJobObject(handle, JobObjectInfoType.ExtendedLimitInformation, extendedInfoPtr, (uint)length)) throw new Exception(string.Format("Unable to set information. Error: {0}", Marshal.GetLastWin32Error())); } /// <summary> /// 进程加入到作业对象中 /// </summary> /// <param name="processHandle">进程句柄</param> /// <returns></returns> public bool AddProcess(IntPtr processHandle) { return AssignProcessToJobObject(handle, processHandle); } /// <summary> /// 进程加入到作业对象中 /// </summary> /// <param name="processId">进程Id</param> /// <returns></returns> public bool AddProcess(int processId) { return AddProcess(Process.GetProcessById(processId).Handle); } /// <summary> /// 销毁作业对象,手动调用则其拥有的所有进程都会退出 /// </summary> public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } /// <summary> /// 销毁作业对象,手动调用则其拥有的所有进程都会退出 /// </summary> public void Close() { CloseHandle(handle); handle = IntPtr.Zero; } private void Dispose(bool disposing) { if (disposed) return; if (disposing) { } Close(); disposed = true; } } [StructLayout(LayoutKind.Sequential)] struct IO_COUNTERS { public UInt64 ReadOperationCount; public UInt64 WriteOperationCount; public UInt64 OtherOperationCount; public UInt64 ReadTransferCount; public UInt64 WriteTransferCount; public UInt64 OtherTransferCount; } [StructLayout(LayoutKind.Sequential)] struct JOBOBJECT_BASIC_LIMIT_INFORMATION { public Int64 PerProcessUserTimeLimit; public Int64 PerJobUserTimeLimit; public UInt32 LimitFlags; public UIntPtr MinimumWorkingSetSize; public UIntPtr MaximumWorkingSetSize; public UInt32 ActiveProcessLimit; public UIntPtr Affinity; public UInt32 PriorityClass; public UInt32 SchedulingClass; } [StructLayout(LayoutKind.Sequential)] public struct SECURITY_ATTRIBUTES { public UInt32 nLength; public IntPtr lpSecurityDescriptor; public Int32 bInheritHandle; } [StructLayout(LayoutKind.Sequential)] struct JOBOBJECT_EXTENDED_LIMIT_INFORMATION 编程客栈 { public JOBOBJECT_BASIC_LIMIT_INFORMATION BasicLimitInformation; public IO_COUNTERS IoInfo; public UIntPtr ProcessMemoryLimit; public UIntPtr JobMemoryLimit; public UIntPtr PeakProcessMemoryUsed; public UIntPtr PeakJobMemoryUsed; } public enum JobObjectInfoType { AssociateCompletionPortInformation = 7, BasicLimitInformation = 2, BasicUIRestrictions = 4, EndOfJobTimeInformation = 6, ExtendedLimitInformation = 9, SecurityLimitInformation = 5, GroupInformation = 11 } #endregion }
三、使用示例
1、正常退出自动结束子进程
.net8.0
using System.Diagnostics; using JobManagement; //创建作业对象 Job _job = new Job(); //打开记事本程序 var ps = new Process(); ps.StartInfo.FileName = "notepad.exe"; ps.Start(); //记事本程序进程加入到作业对象 _job.AddProcess(ps.Handle); //等待3秒后退出程序,记事本程序会自动关闭 Thread.Sleep(3000);
效果预览
2、异常退出自动结束子进程
.net8.0
using System.Diagnostics; using JobManagement; //创建作业对象 Job _job = new Job(); //打开记事本程序 var ps = new Process(); ps.StartInfo.FileName = "notepad.exe"; ps.Start(); //记事本程序进程加入到作业对象 _job.AddProcess(ps.Handle); while(true)Thread.Sleep(3000);
效果预览
总结
本文讲述的内容是Windows多进程开发中比较重要的技术,因为大部分场景主进程退出后子进程应该跟随退出,正常流程中通过代码可以在退出时关闭所有子进程,但是异常崩溃时则不行,会出现遗留子进程。而本文的方法就很好的解决的这个问题,而且也不需要编写任何关闭子进程的相关代码,方便且省心。
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