File Access(XlFileAccess, Object, Object)
Changes the access permissions for the workbook. This might require an updated version to be loaded from the disk.
public void ChangeFileAccess (Microsoft.Office.Interop.Excel.XlFileAccess Mode, object WritePassword, object Notify);
true to notify the user if the file cannot be immediately accessed.
If you have a file open in read-only mode, you do not have exclusive access to the file. If you change a file from read-only to read/write, Microsoft Office Excel must load a new copy of the file to ensure that no changes were made while you had the file open as read-only.
For information on optional parameters, see Optional Parameters in Office Solutions.