I do not know how to implement the Row Updating event in the Grid View.
To finish up then one has to set the Sql Data Source Update Parameters to the desired values. I have set the requisite attributes in the Grid View tag. (Note, in the gridview the Enable View State="False" - if I set it to True I get the standard "Failed to load viewstate. error) One strange thing that I've noticed that makes me think it's a View State problem is that if I change the Command Name of the Update button to "Edit" that postback event does get captured in the Row Command event... Binding form controls is mostly a simple matter of attaching a Data Source and setting your controls to reference the correct field in the Data Source. Binding a Grid View control can sometimes get tricky when using the Visual Studio editor, especially when working with Drop Down List controls within the grid.
I am using a Template Field to display my Edit, Update and Cancel 'buttons' in the first column of the Grid View within respective Item Template and Edit Item Template fields.