Changing DataGrid layout if 'EDIT' is pressed

Question

I have a Dataview that is displayed on my page.  There are 12 columns to the DataGrid.  The user will need to edit 5 of those columns.

I can have everything display in the Datagrid.  THat worked fine.  I also changed the DataGrid so that the 5 columns are 'Template' columns, so that they now appear as TextBoxes instead of labels.

But how do I make them display normal (as labels in a Datagrid), until the user clicks a button at the bottom of the page that says 'EDIT'.  WHen they do this, those 5 columns should now be TextBoxes, for ALL rows of the table.  (They will never edit just one row at a time, but the entire page).