Hello,

I want to change a ProgressBar in a separate Thread.

My current code is the following:

private void changeProgressBarThread()
{
    changeProgressBar();
}

private void changeProgressBar()
{
    toolStripProgressBar1.Maximum = 100;
    for (int i = 0; i <= 100; i++)
    {
       toolStripProgressBar1.Value = i;
           if (i == 100)
              {
               for (int j = 100; j >= 0; j++)
               {
                  toolStripProgressBar1.Value = j;
               }
              i = 0;
           }
       }
}

private void button1_Click(object sender, EventArgs e)
{

    ThreadStart thrdDeleg1 = new ThreadStart(addDataSetThread);
    Thread addDSThrd1 = new Thread(thrdDeleg1);

    ThreadStart thrdDeleg2 = new ThreadStart(changeProgressBarThread);
    Thread addDSThrd2 = new Thread(thrdDeleg2);

    addDSThrd1.Start();
    addDSThrd2.Start();

    while (addDSThrd1.IsAlive)
    {
    if(!addDSThrd1.IsAlive)
            addDSThrd2.Abort();
    }
    addDSThrd1.Join();

    string[] row = new String[3];
    row[0] = searchText_;
    row[1] = results_.count.ToString();
    row[2] = "0";
    dgViewData.Rows.Add(row);

}

My problem is now, that I cannot use the toolStripProgressBar1 object:

"Cross-thread operation not valid: Control '' accessed from a thread
other than the thread it was created on."

I understand the error message but... How can I fix the error?
I do not know how to update my progress bar if I cannot update it in my
seperate thread.

How do you do that?

It would be nice if you could give me a small example.

And my other question concerns the following code lines:

   while (addDSThrd1.IsAlive)
    {
    if(!addDSThrd1.IsAlive)
            addDSThrd2.Abort();
    }

I think these lines of code are not very well/ secure,
because it looks bit like an endless loop.

How do you let another thread (here my progress bar thread) stop if a
long calculation in another thread is finished?

Regards,

Martin