I have used CellValuechanged and CellalueChanging.Whenever the cell is focused and value is not updated or same value is typed these events are not fired.Each time when the focus of cell is lost event should get fired even if value entered is same as prevoius value.

I dont want to use BeforeRowLeave Event?

Which event should I used?

I believe you'll need to use your own editor for the cell instead of letting the grid autocreate one. Then you can hook into the editor's events. I ran into a similar issue the other day and came across this:

http://www.devexpress.com/Support/Center/p/D876.aspx

The relevant part is:
"Another way to implement this goal is to handle the Column RepositoryItem’s EditValueChanged event. In this instance, you will need to assign the Column’s ColumnEdit property to an existing RepositoryItem first."