C#

/* This is a blink label user control --------------------------------*/
public partial class BlinkLabel : Label {

private CancellationTokenSource ts;
private Task task1;

public BlinkLabel()
{ 
   InitializeComponent(); 
}

public void StartBlink()
{
   ts=new CancellationTokenSource();
   CancellationToken ct = ts.Token;

   if ( isRunningTask(task1) ) return;

   task1 = Task.Factory.StartNew(() =>
   {
       while (true)
       {
           ct.ThrowIfCancellationRequested();
           Thread.Sleep(500);
           Visible = !Visible;
                    
       }
    }, ct);

    blinkTask.ContinueWith(t =>
    {
        Visible = false;

    },TaskContinuationOptions.None);

            
}

public void StopBlink()
{
    ts.Cancel();
}

}

/* This is a my main form that use blink label user control--------------------------------*/
public partial class MainForm: Form
{
    public MainForm
   {
       InitializeComponent(); 
      
       blinkLabel1.Text="Blinking message...";
       blinkLabel1.StartBlink(); //Works
       blinkLabel1.StopBlink();  //Not works - blink not stop.
   }
    
}

 try
{
    WebRequest request = WebRequest.Create("http://facebook.com");
    HttpWebResponse response = (HttpWebResponse) request.GetResponse();
    
    MessageBox.Show("I am here!");                
}
catch (Exception ex)
{
    MessageBox.Show("Error Occurred!");
}