For this tutorial I am using Microsoft famous sample database Northwind. Also make sure you are setting Grid View Data Key Fields property to the Primary Key column of the Product Table such as Product ID.
Grid View control Row Command event will give you the Product ID of the product from the Grid View Rows when user will click any of the button in the Grid View. To handle click event of the buttons in Grid View you need to handle Row Command event of the Grid View control.
If you like my work; you can appreciate by leaving your comments, hitting Facebook like button, following on Google , Twitter, Linkedin and Pinterest, stumbling my posts on stumble upon and subscribing for receiving free updates directly to your inbox .Stay tuned and stay connected for more technical updates. Had we used the 'Register Client Script Block', the browser would have executed the Java Script before the text box is on the page.One note will be helpful for you, while describing Columns in Grid View if you are using a boundfield then create objects of the control using cells[index] in the rowupdateing event of Grid View, but if you are using controls itself like Label or textboxes etc then use Fincontrol("stringid"). Net Grid View control with simple Data Set or Data Table, and also explains the methods like Insert, Edit, Update and Delete function in the Grid View control.