Can any one tell me what is the safe way of terminating a thread

Question

I found that thread.Abort() does not terminate the thread properly. It

always throws ThreadAbortException...Can any one tell me how can I safely terminate a

thread.

My code of terminating thread....

private void btnCancel_Click(object sender, EventArgs e)
{

DialogResult dr = MessageBox.Show("Are you sure you want to terminate file backup process","Information",MessageBoxButtons.YesNo,MessageBoxIcon.Information);

            if (dr == DialogResult.Yes)
            {
                try
                {
                    //if (th.ThreadState == ThreadState.Running)
                    if(th.IsAlive)
                    {

                        th.Abort();
                       // th.Join();
                        Thread.Sleep(1000);
                        this.Close();
                    }


                }
                catch (ThreadAbortException ex)
                {
                    MessageBox.Show(ex.ToString());
                }
            }

}

After clicking Cancel if i call that funtion again then that thread does'nt start.

plz help....

Mike Gold · Answer

You might consider closing the form after the thread is terminated. The way to do this is to have the thread call a delegate after it exits the loop using Invoke. Delegate void CloseFormDelegate(); ... CloseForm = new CloseFormDelegate(OnMyEvent); void OnMyEvent() { this.Close() } // user cancelled call this in the thread after it exits the loop this.Invoke(CloseForm);

Suraj Rai · Answer

Tnx for the reply to both of u.... I am getting exception in thread.Abort() not in thread.Sleep()... Mike ...abt ur code i m not getting where to place this code... Actually my application uploads file to server . So wat i m doing is I am calling a function in saparate thread for uploading files like this... private void Form1_Load(object sender EventArgs e) { progressBar1.Step = 1; progressBar1.Value = 0; th = new Thread(new ThreadStart(CalBAckUpFrm)); th.Start(); } public void CalBAckUpFrm() { // Uploading codes } I ve a Cancel button...If user wants to cancel the process in the middle the thread should get terminated.... By luking at ur code i did some changes..like this... public bool boolThreadTerminator = true; public void CalBAckUpFrm() { while (boolThreadTerminator) { //Uploading codes } } private void btnCancel_Click(object sender EventArgs e) { DialogResult dr = MessageBox.Show(Are you sure you want to terminate file backup processInformationMessageBoxButtons.YesNoMessageBoxIcon.Information); if (dr == DialogResult.Yes) { try { if(th.IsAlive) { boolThreadTerminator = false; this.Close(); } } catch (ThreadAbortException ex) { MessageBox.Show(YuntaaClasses.Exceptions.HasIOException(ex) Information MessageBoxButtons.OK MessageBoxIcon.Information); } } } and its not working....when i cancel the form the form gets closed but the uploading still continues in background. I think I did'nt get u properly.... Can u plz help me little....

Mike Gold · Answer

a better way to terminate a thread rather than aborting it (aborting throws an exception) is to set a flag so that the thread will terminate normally. for example bool _flag = true; void mythreadhandler() { while (_flag) { } } Setting the flag to false will terminate the loop exit the method and terminate the thread. -Mike G.

Ripal Soni · Answer

I think you don't need to do thread.sleep() after you abort the thread did you debug your code? it will give you the exact place where you are getting this exception on thread.abort or on thread.sleep if you are creating new thread at the starting of thread then thread.abort should work try comment out that thread.sleep line Good Luck!