thread problem in textbox control access!

Thank you for your answer. You're right, the best way to solve my problem is to use delegate. I tried it and it's work well now.

again, thanks.

here is a sample application that uses 2 threads(the main UI thread, and another thread to loop through numbers).  It updates a textbox from the second thread(non-UI thread) using a delegate. 

namespace ThreadingUIUpdate
{
    public partial class Form1 : Form
    {
        public delegate void UpdateTextCallback(string message);

        public Form1()
        {
            InitializeComponent();
        }

        private void btnStart_Click(object sender, EventArgs e)
        {
            Thread thread = new Thread(new ThreadStart(TestThread));
            thread.Start();
        }

        private void UpdateText(string message)
        {
            textBox1.Text = message;
        }

        private void TestThread()
        {
            for (int i = 0; i <= 1000000000; i++)
            {
                Thread.Sleep(1000);
                textBox1.Invoke(new UpdateTextCallback(this.UpdateText), new object[] { i.ToString() });
            }
        }
    }
}


This is what you need to do.  You are trying to do a cross-thread action, which isn't allowed.  The "Invoke" method will fire the delegate on the thread that owns the control.

Yohann,

The 'TextBoxHandler' code should be there inside the class where the text box is created. Did you try that way?

Nilanka,

I tried your solution of delegate but it seems to doesn't work. The same problem raises ("The calling thread cannot access this object because a different thread owns it."). I don't know wich thread can own the textbox! ...

thank you nilanka for your answer,

the probleme is that i can't acces my textbox via the textboxhandler class. All the controls in my window application aren't public. So How can I access them from the outside?