Any reason you want to use the template grid instead of a normal grid? Because that last one you can edit the fields in the colums.
Good Day! A template grid only provides a View of the data like a DataGrid except you get more flexibility to arrange the values instead of a single row. If you want to edit the values you would have to create a Edit button and link a Edit page to it.
But from what I understand your requirement will more likely be fulfilled by using a List View, am not sure how the Entities are modelled but the List you are showing in template grid can be shown in a List View, make the List View editable and create a table as a container for Column Headings outside the List View.
Good Luck, Regards,