How to add a button in a row of a datagridview?

How can I add a button to a row in gridview using winforms and C#?

some rows have an object associated with some rows. I want to add a button in the row and when the user clicks that button I want a dialog to open up and allow them to edit the object data.

How can I add a button to each row that if the tag property of that row is not null?

and how can I add onClick handler to display the the form when the user can edit the object data?