delphi 检测excel文件真实类型 xls xlsx

  function ISXLS(const FileName: string): boolean;

var

  txt: file;

  bytes: array[0..2] of byte;

  amt: integer;

begin

  FileMode := fmOpenRead;

  AssignFile(txt, FileName);

  Reset(txt, 1);

  try

    BlockRead(txt, bytes, 3, amt);

    result := (amt=3) and (bytes[0] = $D0) and (bytes[1] = $CF) and (bytes[2] = $11);

  finally

    CloseFile(txt);

  end;

end;

  function ISXLSX(const FileName: string): boolean;

var

  txt: file;

  bytes: array[0..2] of byte;

  amt: integer;

begin

  FileMode := fmOpenRead;

  AssignFile(txt, FileName);

  Reset(txt, 1);

  try

    BlockRead(txt, bytes, 3, amt);

    result := (amt=3) and (bytes[0] = $50) and (bytes[1] = $4B) and (bytes[2] = $03);

  finally

    CloseFile(txt);

  end;

end;