Deadlock in System.Diagnostic.Process

Question

I have a small console application and I want to read the output in C#. Therefore I've created this code snippet. The command prompt opens, but nothing is displayed.

System.Diagnostics.Process process = new System.Diagnostics.Process();
process.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Normal;
process.StartInfo.FileName = DirectoryPath + "Test.exe";
process.StartInfo.Arguments = "-showAll";
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.Start();
process.WaitForExit(2000);
String strOutput = process.StandardOutput.ReadToEnd();

If I remove UseShellExecute , RedirectStandardOutput and the last line, the command prompt opens and the Test.exe is shown, but I need the output as String and so I have to use these attributes to read the StandardOutput

I've also tried to set a timeout of 2 seconds ( process.WaitForExit(2000) ), but the empty command prompt does not close after 2 seconds.

If I close the empty command prompt manually in debug mode, the variable strOutput has my requested information.

Answer 1

To avoid deadlock you have to read the output stream before you wait to exit. So try :

    System.Diagnostics.Process process = new System.Diagnostics.Process();
    process.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Normal;
    process.StartInfo.FileName = DirectoryPath + "Test.exe";
    process.StartInfo.Arguments = "-showAll";
    process.StartInfo.UseShellExecute = false;
    process.StartInfo.RedirectStandardOutput = true;
    process.Start();
    String strOutput = process.StandardOutput.ReadToEnd();
    process.WaitForExit();