If you already have any kind of button, whether it be a plain button, LinkButton, or Imagebutton, in a TemplateField, within a GridView, you can add ‘Select’ features to it, just as if you had added a ‘Select’ column.

All you need to do is add ‘Select’ to the CommandName property. Then, anything you could do with the Select CommandField, you can do with your own TemplateField.