In a WinForm C# application I have a Barcode_textbox. In TextChanged
event I have an SQL query to check for the TextBox.Text value in the database which is the barc
Use timer in this fashion that when user stops typing in your textbox for a given small time say 1 second only then get data from database...
Also you can place a check at the characters typed by user with a counter such that when it exceeds that minimum(the minimum size that your key can be) get the data...Will save much time