how to call a function from a existing thread plz help

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hi i am calling a function but it is giving me error:
Cross-thread operation not valid: Control 'textBox1' accessed from a thread other than the thread it was created on.
plz help

C#

private void button1_Click(object sender, System.EventArgs e)
        {
            _t = new Thread(new ThreadStart(DoSomething));
            _t.Start();
        }
private Thread _t;
        private void DoSomething()
        {
            try
            {
                while(true)
                {
                   write(str);
                }
            }
            catch (ThreadAbortException ex)
            {
                MessageBox.Show("Loop break");
                return;
            }
        }
 public void WriteText(string str)
{
/*do something*/
}

 private void button2_Click(object sender, System.EventArgs e)
  {
            _t.Abort();
  }

Posted 11-Sep-12 3:43am

Member 9092048

Updated 11-Sep-12 3:51am

JF2015

v2

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[no name] 11-Sep-12 9:55am

Would you accept help from someone other than "plz"?

Member 9092048 11-Sep-12 9:56am

yes

2 solutions

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**JF2015** · Accepted Answer · 2012-09-11T03:55:00

Solution 1

Hi,

you can try this code:

C#

private delegate void WriteTextCallback(string str);
public void WriteText(string str)
{
   if (this.InvokeRequired)
   {
      BeginInvoke(new WriteTextCallback(WriteText), new object[] { str });
      return;
   }
   TextBox1.Text = "Hallo";
}

Posted 11-Sep-12 3:55am

JF2015

Comments

Espen Harlinn 11-Sep-12 10:09am

5'ed!

Member 9092048 11-Sep-12 10:40am

thanks

RaisKazi 11-Sep-12 15:59pm

My 5!

OriginalGriff · Accepted Answer · 2012-09-11T03:56:00

UI controls can only be accessed from the thread they are created on (the UI thread). If you try to do so from a different thread, you get the error.
You need to Invoke the control. Here is a generic way to do it:

C#

private void AddNewTab(string tabName)
    {
    if (InvokeRequired)
        {
        Invoke(new MethodInvoker(delegate { AddNewTab(tabName); }));
        }
    else
        {
        TabPage tp = new TabPage(tabName);
        myTabControl.TabPages.Add(tp);
        }
    }