How to wait for the process to start?

Question

My application needs to wait until a specific process begins. I do it like this.

while (Process.GetProcessesByName("someProcess").Length == 0) { Thread.Sleep(100); } 

Is there another way (more elegant) how to do this, with functionality similar to WaitForExit ()? Thanks for answers.

Answer 1

Take a look at the ManagementEventWatcher class.

In particular, the sample code at the bottom of the link shows you how to configure ManagementEventWatcher to be notified when a new process is created.

Code copied from the sample MSDN code (may stand a little clean):

 using System; using System.Management; // This example shows synchronous consumption of events. // The client is blocked while waiting for events. public class EventWatcherPolling { public static int Main(string[] args) { // Create event query to be notified within 1 second of // a change in a service WqlEventQuery query = new WqlEventQuery("__InstanceCreationEvent", new TimeSpan(0,0,1), "TargetInstance isa \"Win32_Process\""); // Initialize an event watcher and subscribe to events // that match this query ManagementEventWatcher watcher = new ManagementEventWatcher(); watcher.Query = query; // times out watcher.WaitForNextEvent in 5 seconds watcher.Options.Timeout = new TimeSpan(0,0,5); // Block until the next event occurs // Note: this can be done in a loop if waiting for // more than one occurrence Console.WriteLine( "Open an application (notepad.exe) to trigger an event."); ManagementBaseObject e = watcher.WaitForNextEvent(); //Display information from the event Console.WriteLine( "Process {0} has been created, path is: {1}", ((ManagementBaseObject)e ["TargetInstance"])["Name"], ((ManagementBaseObject)e ["TargetInstance"])["ExecutablePath"]); //Cancel the subscription watcher.Stop(); return 0; } } 

Edit

A simplified example with the added filter TargetInstance.Name = 'someProcess' .

  var query = new WqlEventQuery( "__InstanceCreationEvent", new TimeSpan(0, 0, 1), "TargetInstance isa \"Win32_Process\" and TargetInstance.Name = 'someProcess'" ); using(var watcher = new ManagementEventWatcher(query)) { ManagementBaseObject e = watcher.WaitForNextEvent(); //someProcess created. watcher.Stop(); } 

Answer 2

As far as I know, there is nothing in the Process class that makes it simple.

If you don't have control over the source code in the subprocess, you should probably go with the WMI solution that Calgary Coder provided.

If you have control over the code in a subprocess, then there are several additional ways to solve this problem. I used WCF (using IPC binding ), .NET Remoting and Mutex .

The advantage of these solutions is that the subprocess must select it. A subprocess can wait for its initialization startup procedures to complete before letting the parent application know that it is "ready."

Each of these links has samples that should give you a start to solve this problem. If you are interested in going with a specific one and have problems, let me know and I will send sample code for this specific solution.