Process Information and Notifications using WMI

/***********************************************************************************************
 * File Name	: ProcessInfo.cs
 * Description	: This class demonstrates the use of WMI.
 *				  It provides a static method to query the list of running processes.
 *				  And it provides two events to delegate when an application has been started.
 * 
 * Author		: Asghar Panahy
 * Date			: 26-oct-2005
 ***********************************************************************************************/
using System;
using System.Data;
using System.Management;		

namespace Win32Process
{
	/// <summary>
	/// ProcessInfo class.
	/// </summary>
	public class ProcessInfo
	{
		// defenition of the delegates
		public delegate void StartedEventHandler(object sender, EventArgs e);
		public delegate void TerminatedEventHandler(object sender, EventArgs e);
		
		// events to subscribe
		public StartedEventHandler Started = null; 
		public TerminatedEventHandler Terminated = null; 

		// WMI event watcher
		private ManagementEventWatcher watcher;
		
		// The constructor uses the application name like notepad.exe
		// And it starts the watcher
		public ProcessInfo(string appName)
		{
			// querry every 2 seconds
			string pol = "2"; 

			string queryString = 
				"SELECT *" +
				"  FROM __InstanceOperationEvent " + 
				"WITHIN  " + pol +
				" WHERE TargetInstance ISA 'Win32_Process' "  + 				
				"   AND TargetInstance.Name = '" + appName + "'";
								
			// You could replace the dot by a machine name to watch to that machine
			string scope = @"\\.\root\CIMV2";
			
			// create the watcher and start to listen
			watcher  = new ManagementEventWatcher(scope, queryString);
			watcher.EventArrived += new EventArrivedEventHandler(this.OnEventArrived);			
			watcher.Start();
		}
		public void Dispose()
		{
			watcher.Stop();
			watcher.Dispose();
		}
		public static DataTable RunningProcesses()
		{
			/* One way of constructing a query
			string className = "Win32_Process";
			string condition = "";
			string[] selectedProperties = new string[] {"Name", "ProcessId", "Caption", "ExecutablePath"};
			SelectQuery query = new SelectQuery(className, condition, selectedProperties);
			*/
			
			// The second way of constructing a query
			string queryString = 
				"SELECT Name, ProcessId, Caption, ExecutablePath" + 
				"  FROM Win32_Process";
								
			SelectQuery query = new SelectQuery(queryString);
			ManagementScope scope = new System.Management.ManagementScope(@"\\.\root\CIMV2");
			
			ManagementObjectSearcher searcher = new ManagementObjectSearcher(scope, query);
			ManagementObjectCollection processes = searcher.Get();
			
			DataTable result = new DataTable();
			result.Columns.Add("Name", Type.GetType("System.String"));
			result.Columns.Add("ProcessId", Type.GetType("System.Int32"));
			result.Columns.Add("Caption", Type.GetType("System.String"));
			result.Columns.Add("Path", Type.GetType("System.String"));
			
			foreach(ManagementObject mo in processes)
			{
				DataRow row = result.NewRow();
				row["Name"] = mo["Name"].ToString();
				row["ProcessId"] = Convert.ToInt32(mo["ProcessId"]);
				if (mo["Caption"]!= null)
					row["Caption"] = mo["Caption"].ToString();
				if (mo["ExecutablePath"]!= null)
					row["Path"] = mo["ExecutablePath"].ToString();
				result.Rows.Add( row );
			}
			return result;
		} 
		private void OnEventArrived(object sender, System.Management.EventArrivedEventArgs e)
		{
			try 
			{
				string eventName = e.NewEvent.ClassPath.ClassName;

				if (eventName.CompareTo("__InstanceCreationEvent")==0)
				{
					// Started
					if (Started!=null) 
						Started(this, e);
				}
				else if (eventName.CompareTo("__InstanceDeletionEvent")==0)
				{
					// Terminated
					if (Terminated!=null) 
						Terminated(this, e);

				}				
			}
			catch (Exception ex)
			{
				System.Diagnostics.Debug.WriteLine(ex.Message);
			}
		}
		
	}
}