Exclusive Access Method
Assigns the current user exclusive access to the workbook that is open as a shared list.
public bool ExclusiveAccess ();
This method saves any changes made to the workbook and requires other users who have the workbook open to save their changes to a different file.
If the workbook is not open as a shared list, this method fails. To determine whether a workbook is open as a shared list, use the MultiUserEditing property.