[Gtk-sharp-list] Application.Invoke and threads: strange behavior

[amartinez]

Hi,

Attached is a very little Gtk# example which uses a Thread to execute
the process 'ping 127.0.0.1 -c 7' and refresh both the standard output and
a TextView.

It can be compiled with mcs or gmcs with
$ mcs -pkg:gtk-sharp-2.0 test.cs

The execution of the program shows different outputs in the TextView and
the console.
It seems like the string 'tmp' forgets its last values inside the delegate.

I use mono and mcs version 1.1.9.2 and Gtk# version 2.3.92 over Debian Sid.

What's the reason of this strange behavior?

Regards,

-- 
Antonio Martínez Alvarez
	using System;
	using System.IO;
	using System.Diagnostics;
	using System.Threading;
	using Gtk;

	
	class App
	{
		public static void Main()
		{
			new test_threads();
		}
	}
	
	

	class test_threads
	{
		Process p;
		ProcessStartInfo psi;
	
		Window win = null;
		TextView textview = null;		
		
		static TextBuffer buff = null;
		static string tmp; // string read in ThreadFunc
						
		public test_threads()
		{
			Application.Init ();
			
			win = new Window ("Test");
			win.SetDefaultSize (500, 300);	
			win.DeleteEvent += new DeleteEventHandler (delegate {Application.Quit();});
			
			VBox box = new VBox (false, 0);

			Button btn = new Button ("ping 127.0.0.1 -c 7");
			btn.Clicked += new EventHandler (btn_click);
			box.PackStart (btn, true, true, 1);

			Button btn2 = new Button ("Clear TextView");
			btn2.Clicked += delegate {buff.Text = "";};
			box.PackStart (btn2, true, true, 1);			

			ScrolledWindow sw = new ScrolledWindow ();
			textview = new TextView();

			sw.Add(textview);
			box.PackStart (sw, true, true, 1);
			
			buff = textview.Buffer;
			win.Add(box);
			win.ShowAll ();
			
			Application.Run();
		}	

		void btn_click (object obj, EventArgs args)
		{		
			psi = new ProcessStartInfo();
			psi.FileName = "ping";
			psi.Arguments = "127.0.0.1 -c 7";
			psi.RedirectStandardOutput = true;
			psi.RedirectStandardError = true;
			psi.UseShellExecute = false;
			
			p = Process.Start(psi);
			
			Thread thr = new Thread (new ThreadStart (ThreadFunc));
			thr.Start ();
		}
		
		public void ThreadFunc()
		{			
			while ((tmp = p.StandardOutput.ReadLine()) != null) 
			{
				Console.WriteLine (tmp);
				Application.Invoke (delegate 
					{ 
						buff.Text += System.Environment.NewLine + tmp;
					}
				);				
			}			
		}
		
	}

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