I have got error I will show You code

Question

sql code

select * from gridview

insert into gridview values (1,'romesh',9043852844,'dpm','laxminarayena')

insert into gridview values (2,'rr',804593839,'spk','narayena')

insert into gridview values (3,'ggf',773682388,'ich','rom')

insert into gridview values (4,'vvv',8803774443,'kotari','surya')

insert into gridview values (5,'hhh',98480004374,'pbm','llb')

 gridview id Gv

Answer 1

first of all there is an error
  if (startTime < endTime)
                {
                    richTextRxMessage.Text = richTextRxMessage + Convert.ToString(elapsedTime);
                }
it needs to be:
      richTextRxMessage.Text = richTextRxMessage.Text + Convert.ToString(elapsedTime);