make one Enum variable like
public Enum Action
{
Add, Edit
};
make one public property of it like
public Action EnumAction
{
get;
set;
}
now when u want to make action "add" then simply assing the value of EnumAction = Action.Add
and when u want to make action "edit" then simply assing the value of EnumAction = Action.Edit
and check it at your button click event...