Gridview Template field how to update

I have template field with textbox in gridview.
When i click on the cell I have a textbox_load event which pulls in my default date. Now I want to update the value in the textbox to database if user is not updating/not changing the default value and clicks on any other cell in the gridview.
I have code to update to the database and show on the grid view if user updated the cell or textbox text value using texbox_textchange event.
How should i update the value if user does not change any value I want to save the default value to database only if user clicks on a different cell in the gridview if he doenot click on any other cell in the gridview default value should not be updated to the database.
Thanks,
Satya Chenna