我试图做一些看似超出System.Diagnostics.Process对象范围的事情。可接受的答案可以提出不同的方法，只要它使用.net 4.5 / c＃5。
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以这种格式输出。
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。我希望每当它改变时读取该行，这样我就可以移动一个进度条，让用户知情。
首先，我尝试阅读Process.StandardOutput，但在整个过程完成之前，它不提供任何数据。其次，我尝试拨打Process.BeginOutputReadLine()并连接事件Process.OutputDataReceived，但只有在线路完成后才会触发。
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<string, string> 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<String, String> 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;
}
有人可以帮我实时阅读此输出吗？
答案 0 :(得分：4)
这是您的问题的解决方案，但有点棘手，因为gdalwarp.exe阻止标准输出，您可以将其输出重定向到文件并读取它的更改。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<string, string> 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<string, string> EnviroVariables = null, bool Trace = false, bool ThrowError = true, int ValidExitCode = 0, Action<string, string> 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<String, String> 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);
}