I've been troubleshooting all day. After doing some research and a lot of trial and error, it seems I've been able to narrow down the issue to the fact that my call to process.Start() doesn't work on a timer thread. The code below works when running on the main thread. Put that exact same code in a timer callback, and it hangs. Why? How do I get it to work with a timer?
private static void RunProcess()
{
var process = new Process();
process.StartInfo.FileName = "cmd";
process.StartInfo.Arguments = "/c exit";
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.RedirectStandardInput = true;
process.StartInfo.RedirectStandardOutput = true;
process.Start(); // code hangs here, when running on background thread
process.StandardOutput.ReadToEnd();
process.WaitForExit();
}
EDIT
As a test, I used this exact same code on another laptop, and I experienced the same problem. This is complete code that can be pasted into a console app. process.Start() hangs, but as soon as I hit any key to end, process.Start() completes before the program ends.
private static System.Timers.Timer _timer;
private static readonly object _locker = new object();
static void Main(string[] args)
{
ProcessTest();
Console.WriteLine("Press any key to end.");
Console.ReadKey();
}
private static void ProcessTest()
{
Initialize();
}
private static void Initialize()
{
int timerInterval = 2000;
_timer = new System.Timers.Timer(timerInterval);
_timer.Elapsed += new ElapsedEventHandler(OnTimerElapsed);
_timer.Start();
}
private static void OnTimerElapsed(object sender, ElapsedEventArgs e)
{
if (!Monitor.TryEnter(_locker)) { return; } // Don't let multiple threads in here at the same time.
try
{
RunProcess();
}
finally
{
Monitor.Exit(_locker);
}
}
private static void RunProcess()
{
var process = new Process();
process.StartInfo.FileName = "cmd";
process.StartInfo.Arguments = "/c exit";
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.RedirectStandardInput = true;
process.StartInfo.RedirectStandardOutput = true;
process.Start(); // ** HANGS HERE **
process.StandardOutput.ReadToEnd();
process.WaitForExit();
}
