Enumeration OpenFileMode

  Read         bit 0   The file is opened for reading. If this bit is not
                       set the Read Method cannot be executed.

 Write         bit 1   The file is opened for writing. If this bit is not
                       set the Write Method cannot be executed.

 Append        3   When the Append bit is set the file is opened at end
                   of the file, otherwise at begin of the file.
                   The SetPosition Method can be used to change the position.

WriteEraseExisting EraseExisting 2 This bit can only be set if the file is opened for writing (Write bit is set). The existing content of the file is erased and an empty file is provided.