C#

private void btn_simulate_Click(object sender, EventArgs e)<br />
        {<br />
            this.btn_simulate.Enabled = false;<br />
            this.btn_stop.Enabled = true;<br />
            closeThreadRequested = false;<br />
            if (!packetsMovingThread.IsBusy)<br />
                packetsMovingThread.RunWorkerAsync();<br />
            <br />
        }<br />
        /// <summary><br />
        /// When press the button stop simulation <br />
        /// </summary><br />
        private void btn_stop_Click(object sender, EventArgs e)<br />
        {<br />
            closeThreadRequested = true;<br />
            this.btn_stop.Enabled = false;<br />
            this.btn_simulate.Enabled = true;<br />
            if (packetsMovingThread.IsBusy)<br />
                packetsMovingThread.CancelAsync();<br />
        }<br />
        /// <summary><br />
        /// An event handler that called when thread of background task begin   <br />
        /// </summary><br />
        private void packetsMovingThread_DoWork(object sender, DoWorkEventArgs e)<br />
        {<br />
            BackgroundWorker worker = sender as BackgroundWorker;<br />
            if (worker.CancellationPending)<br />
                e.Cancel = true;<br />
            else<br />
                dataPacket.simulate(lineArray, closeThreadRequested, ref source_pnt,<br />
                    ref destination_pnt, packetsMovingThread);<br />
        }<br />
        /// <summary><br />
        /// An event handler that called when thread of background task Aborted<br />
        /// for any reason(Error,Cancel,Normal Completion)  <br />
        /// </summary><br />
        private void packetsMovingThread_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)<br />
        {<br />
            if (e.Error != null)<br />
                MessageBox.Show(e.Error.Message);<br />
            else if (e.Cancelled)<br />
                MessageBox.Show("Cancelled");<br />
        }<br />
        /// <summary><br />
        /// An event handler that called when thread of background task has changes in <br />
        /// its state or by calling ReportChanges() method<br />
        /// </summary><br />
        private void packetsMovingThread_ProgressChanged(object sender, ProgressChangedEventArgs e)<br />
        {<br />
            if (closeThreadRequested == false && !(source_pnt.IsEmpty))<br />
            {<br />
                dataPacket.drawPacket(this.CreateGraphics(), source_pnt);<br />
            }<br />
            Invalidate(drawingFrame);<br />
            // update here make bad effect on memory<br />
            //Update(); <br />
        }

public void drawPacket(Graphics grfx, Point location)<br />
     {<br />
         Pen pen = new Pen(type);<br />
         SolidBrush solidBrush = new SolidBrush(type);<br />
         grfx.DrawRectangle(pen, location.X, location.Y, 4, 4);<br />
         grfx.FillRectangle(solidBrush, location.X, location.Y, 4, 4);<br />
         pen.Dispose();<br />
         solidBrush.Dispose();<br />
     }