C＃如何用另一个单击事件终止单击事件处理程序

Question

I have a click-event handler to a button that forms an ssh connection. I want to terminate this function with another "cancel" button click.

However, when executing an event handler, "cancel" click event handler doesn't run while the first handler executing. I want to override the first handler with "cancel" handler.

private void button_sshconnection_Click(object sender, EventArgs e)
        { /* some code to create ssh connection */ }

private void button_cancel_Click(object sender, EventArgs e)
        { /* some code to terminate button_sshconnection_Click */ }

I tried a code-structure like the above code but as I said second function doesnt run while the first function running. If the structure is wrong, can someone tell me how to do this job.

Thanks in advance,

Onur

Answer 1

You can try implementing async version of your routine, eg

   private CancellationTokenSource m_Cancellation;

   private async void button_sshconnection_Click(object sender, EventArgs e) {
     // if method is executing, do nothing. Alternative: cancel and start again   
     if (m_Cancellation != null)
       return;

     try { 
       using (m_Cancellation = new CancellationTokenSource()) {
         var token = m_Cancellation.Token;

         await Task.Run(() => {
           //TODO: implement your logic here, please, note that cancellation is cooperative
           // that's why you should check token.IsCancellationRequested

         }, token);
       }
     }
     finally {
       m_Cancellation = null;  
     }
   }

   private void button_cancel_Click(object sender, EventArgs e) {
     // If we can cancel, do it
     m_Cancellation?.Cancel();
   }