在收到新行之前读取Process StandardOutput
我正在尝试做一些看起来超出System.Diagnostics.Process对象范围的事情。 只要使用.net 4.5 / c＃5，可接受的答案就可以提出不同的方法。
我的程序正在调用gdalwarp.exe来对大型tiff文件执行长时间运行的进程。 Galwarp.exe以此格式输出。
Creating output file that is 6014P x 4988L. Processing input file [FileName].tiff. Using band 4 of source image as alpha. Using band 4 of destination image as alpha. 0...10...20...30...40...50...60...70...80...90...100 - done. 最后一行缓慢流入以指示进度。 我想在每次更改时读取该行，以便我可以移动进度条，让用户知情。
首先，我尝试读取Process.StandardOutput但在整个过程完成之前，它不会提供任何数据。 其次，我尝试调用Process.BeginOutputReadLine()并连接事件Process.OutputDataReceived但它只在一行完成时触发。
这是对Execute GDalWarp.exe的调用。
public static void ResizeTiff(string SourceFile, string DestinationFile, float ResolutionWidth, float ResolutionHeight, Guid ProcessId) { var directory = GDalBin; var exe = Path.Combine(directory, "gdalwarp.exe"); var args = " -ts " + ResolutionWidth + " " + ResolutionHeight + " -r cubic -co \"TFW=YES\" \"" + SourceFile + "\" \"" + DestinationFile + "\""; ExecuteProcess(exe, args, null, directory, 0, null, true, true, 0); }
这是我在静态函数中的工作代码，它只在进程退出后读取输出。
public static string ExecuteProcess(string FilePath, string Args, string Input, string WorkingDir, int WaitTime = 0, Dictionary EnviroVariables = null, bool Trace = false, bool ThrowError = true, int ValidExitCode = 0) { var processInfo = "FilePath: " + FilePath + "\n" + (WaitTime > 0 ? "WaitTime: " + WaitTime.ToString() + " ms\n" : "") + (!string.IsNullOrEmpty(Args) ? "Args: " + Args + "\n" : "") + (!string.IsNullOrEmpty(Input) ? "Input: " + Input + "\n" : "") + (!string.IsNullOrEmpty(WorkingDir) ? "WorkingDir: " + WorkingDir + "\n" : "") + (EnviroVariables != null && EnviroVariables.Count > 0 ? "Environment Variables: " + string.Join(", ", EnviroVariables.Select(a => a.Key + "=" + a.Value)) + "\n" : ""); if(Trace) Log.Debug("Running external process with the following parameters:\n" + processInfo); var startInfo = (string.IsNullOrEmpty(Args)) ? new ProcessStartInfo(FilePath) : new ProcessStartInfo(FilePath, Args); if (!string.IsNullOrEmpty(WorkingDir)) startInfo.WorkingDirectory = WorkingDir; startInfo.UseShellExecute = false; startInfo.RedirectStandardOutput = true; startInfo.RedirectStandardError = true; startInfo.CreateNoWindow = true; if (!string.IsNullOrEmpty(Input)) startInfo.RedirectStandardInput = true; if (EnviroVariables != null) foreach (KeyValuePair entry in EnviroVariables) startInfo.EnvironmentVariables.Add(entry.Key, entry.Value); var process = new Process(); process.StartInfo = startInfo; if (process.Start()) { if (Input != null && Input != "") { process.StandardInput.Write(Input); process.StandardInput.Close(); } var standardError = ""; var standardOutput = ""; int exitCode = 0; var errorReadThread = new Thread(new ThreadStart(() => { standardError = process.StandardError.ReadToEnd(); })); var outputReadTread = new Thread(new ThreadStart(() => { standardOutput = process.StandardOutput.ReadToEnd(); })); errorReadThread.Start(); outputReadTread.Start(); var sw = Stopwatch.StartNew(); bool timedOut = false; try { while (errorReadThread.IsAlive || outputReadTread.IsAlive) { Thread.Sleep(50); if (WaitTime > 0 && sw.ElapsedMilliseconds > WaitTime) { if (errorReadThread.IsAlive) errorReadThread.Abort(); if (outputReadTread.IsAlive) outputReadTread.Abort(); timedOut = true; break; } } if (!process.HasExited) process.Kill(); if (timedOut) throw new TimeoutException("Timeout occurred during execution of an external process.\n" + processInfo + "Standard Output: " + standardOutput + "\nStandard Error: " + standardError); exitCode = process.ExitCode; } finally { sw.Stop(); process.Close(); process.Dispose(); } if (ThrowError && exitCode != ValidExitCode) throw new Exception("An error was returned from the execution of an external process.\n" + processInfo + "Exit Code: " + exitCode + "\nStandard Output: " + standardOutput + "\nStandard Error: " + standardError); if (Trace) Log.Debug("Process Exited with the following values:\nExit Code: {0}\nStandard Output: {1}\nStandard Error: {2}", exitCode, standardOutput, standardError); return standardOutput; } else return null; }
谁能帮我实时读取这个输出？
这是你的问题的解决方案，但有点棘手，因为gdalwarp.exe阻止标准输出，你可以将其输出重定向到一个文件并读取它的变化。 可以使用FileSystemWatcher来检测文件中的更改，但有时它不够可靠。 如果OutputCallback不为null，则在outputReadThread中使用下面的文件大小更改的简单轮询方法。
这是对ExecuteProcess的调用，带有回调以立即接收进程输出。
public static void ResizeTiff(string SourceFile, string DestinationFile, float ResolutionWidth, float ResolutionHeight, Guid ProcessId) { var directory = GDalBin; var exe = Path.Combine(directory, "gdalwarp.exe"); var args = " -ts " + ResolutionWidth + " " + ResolutionHeight + " -r cubic -co \"TFW=YES\" \"" + SourceFile + "\" \"" + DestinationFile + "\""; float progress = 0; Action callback = delegate(string fullOutput, string newOutput) { float value; if (float.TryParse(newOutput, out value)) progress = value; else if (newOutput == ".") progress += 2.5f; else if (newOutput.StartsWith("100")) progress = 100; }; ExecuteProcess(exe, args, null, directory, 0, null, true, true, 0, callback); }
这是一个调用任何进程并在结果发生时接收结果的函数。
public static string ExecuteProcess(string FilePath, string Args, string Input, string WorkingDir, int WaitTime = 0, Dictionary EnviroVariables = null, bool Trace = false, bool ThrowError = true, int ValidExitCode = 0, Action OutputChangedCallback = null) { var processInfo = "FilePath: " + FilePath + "\n" + (WaitTime > 0 ? "WaitTime: " + WaitTime.ToString() + " ms\n" : "") + (!string.IsNullOrEmpty(Args) ? "Args: " + Args + "\n" : "") + (!string.IsNullOrEmpty(Input) ? "Input: " + Input + "\n" : "") + (!string.IsNullOrEmpty(WorkingDir) ? "WorkingDir: " + WorkingDir + "\n" : "") + (EnviroVariables != null && EnviroVariables.Count > 0 ? "Environment Variables: " + string.Join(", ", EnviroVariables.Select(a => a.Key + "=" + a.Value)) + "\n" : ""); string outputFile = ""; if (OutputChangedCallback != null) { outputFile = Path.GetTempFileName(); Args = "/C \"\"" + FilePath + "\" " + Args + "\" >" + outputFile; FilePath = "cmd.exe"; } var startInfo = (string.IsNullOrEmpty(Args)) ? new ProcessStartInfo(FilePath) : new ProcessStartInfo(FilePath, Args); if (!string.IsNullOrEmpty(WorkingDir)) startInfo.WorkingDirectory = WorkingDir; startInfo.UseShellExecute = false; startInfo.CreateNoWindow = true; if (OutputChangedCallback == null) { startInfo.RedirectStandardOutput = true; startInfo.RedirectStandardError = true; } else { startInfo.RedirectStandardOutput = false; startInfo.RedirectStandardError = false; } if (!string.IsNullOrEmpty(Input)) startInfo.RedirectStandardInput = true; if (EnviroVariables != null) foreach (KeyValuePair entry in EnviroVariables) startInfo.EnvironmentVariables.Add(entry.Key, entry.Value); var process = new Process(); process.StartInfo = startInfo; if (process.Start()) { if (Trace) Log.Debug("Running external process with the following parameters:\n" + processInfo); try { if (!string.IsNullOrEmpty(Input)) { process.StandardInput.Write(Input); process.StandardInput.Close(); } var standardError = ""; var standardOutput = ""; int exitCode = 0; Thread errorReadThread; Thread outputReadThread; if (OutputChangedCallback == null) { errorReadThread = new Thread(new ThreadStart(() => { standardError = process.StandardError.ReadToEnd(); })); outputReadThread = new Thread(new ThreadStart(() => { standardOutput = process.StandardOutput.ReadToEnd(); })); } else { errorReadThread = new Thread(new ThreadStart(() => { })); outputReadThread = new Thread(new ThreadStart(() => { long len = 0; while (!process.HasExited) { if (File.Exists(outputFile)) { var info = new FileInfo(outputFile); if (info.Length != len) { var content = new StreamReader(File.Open(outputFile, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)).ReadToEnd(); var newContent = content.Substring((int)len, (int)(info.Length - len)); len = info.Length; OutputChangedCallback.Invoke(content, newContent); } } Thread.Sleep(10); } })); } errorReadThread.Start(); outputReadThread.Start(); var sw = Stopwatch.StartNew(); bool timedOut = false; try { while (errorReadThread.IsAlive || outputReadThread.IsAlive) { Thread.Sleep(50); if (WaitTime > 0 && sw.ElapsedMilliseconds > WaitTime) { if (errorReadThread.IsAlive) errorReadThread.Abort(); if (outputReadThread.IsAlive) outputReadThread.Abort(); timedOut = true; break; } } if (!process.HasExited) process.Kill(); if (timedOut) throw new TimeoutException("Timeout occurred during execution of an external process.\n" + processInfo + "Standard Output: " + standardOutput + "\nStandard Error: " + standardError); exitCode = process.ExitCode; } finally { sw.Stop(); process.Close(); process.Dispose(); } if (ThrowError && exitCode != ValidExitCode) throw new Exception("An error was returned from the execution of an external process.\n" + processInfo + "Exit Code: " + exitCode + "\nStandard Output: " + standardOutput + "\nStandard Error: " + standardError); if (Trace) Log.Debug("Process Exited with the following values:\nExit Code: {0}\nStandard Output: {1}\nStandard Error: {2}", exitCode, standardOutput, standardError); return standardOutput; } finally { FileUtilities.AttemptToDeleteFiles(new string[] { outputFile }); } } else throw new Exception("The process failed to start.\n" + processInfo); }