Take a look at the page load if you are binding on post back then the values get updated before you are able to access them.
Follow this link for more details --While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference.
I have got another columns for information like Room Type and have got a button Edit.
When I click on Edit I have Update and Cancel and then I write on the row to update the Price but when I click Update all is the same and error missing.
" Select Command="SELECT a.tenantcode, a.name, a.fixedrate, a.percentrate, a.percentage, b.locationd, c.status FROM TENANTNEW AS a INNER JOIN LOCATION AS b ON a.
I need to do the updating operation on what row is clicked.A Grid View Update Event Args object is passed to the event-handling method, which enables you to determine the index of the current row and to indicate that the update operation should be canceled.To cancel the update operation, set the collections, if necessary, before the values are passed to the data source.event is raised when a row's Update button is clicked, but after the Grid View control updates the row.This enables you to provide an event-handling method that performs a custom routine, such as checking the results of the update operation, whenever this event occurs.