but, i dont think you wil need a thread for this, in Start_Click event write your logic, in that have a loop which can read 50 rows, disable the start button until 50 rows are read, then enable it, again for the next click, read the next 50 rows.
When a button is pressed, the focus will be moving on to button,
you can do this,
once the operation on button_click is done, before the event exits, based on your logic call the last line for either textbox1.focus(); or textbox2.focus();
this should be a simple option.
well, u got the answer with you, it is because you are passing a floating point value to integer u r getting the overflow exception.
check the column in your database, make sure what data type your backend is following, and then also make sure what are you in the text box, also make sure you are converting the same to what data type it is specified in data base.
Thanks, once this is solved, make sure you mark this thread as solved.