private void dequeueButton_Click(object sender, EventArgs e)
 {
     if (waitingQueueListview.Items.Count !=0)
     {
         Customer dequeueCustomer = new Customer();
         dequeueCustomer = customerQueue.Dequeue();
         dequeueSerialNoTextBox.Text = dequeueCustomer.serialNo;
         dequeueNameTextBox.Text = dequeueCustomer.name;
         dequeueComplainTextBox.Text = dequeueCustomer.complain;
         waitingQueueListview.Items.RemoveAt(0);
     }
     else
     {
         MessageBox.Show("Don't Waiting Any Customer");
     }
 }
        private void enqueueButton_Click(object sender, EventArgs e)
        {
            if (enqueueNameTextBox.Text != "" && enqueueComplainTextBox.Text != "")
            {
                Customer aCustomer = new Customer();
                aCustomer.serialNo = Convert.ToString(++count);
                aCustomer.name = enqueueNameTextBox.Text;
                aCustomer.complain = enqueueComplainTextBox.Text;

                customerQueue.Enqueue(aCustomer);

                //waitingQueueListview.Items.Clear();
                ListViewItem item = new ListViewItem(aCustomer.serialNo);
                item.SubItems.Add(aCustomer.name);
                item.SubItems.Add(aCustomer.complain);
                waitingQueueListview.Items.Add(item);
            }
            else
            {
                MessageBox.Show("Please Enter All Data");
            }
            enqueueNameTextBox.Text = string.Empty;
            enqueueComplainTextBox.Text = string.Empty;
        }