引言: 也就是该字符串中不能够包含/\?*:<>|"

function CheckValidFileName(AFileName: string): Boolean;
var
  Handle: THandle;
begin
  Result := True;
  if FileExists(AFileName) then begin
    ShowMessage(AFileName   ' 已存在!');
    Exit;
  end;      Handle := CreateFile(PChar(AFileName),
                       GENERIC_READ or GENERIC_WRITE,
                       0,
                       nil,
                       CREATE_NEW,
                       0,
                       0);
  if Handle <> INVALID_HANDLE_VALUE then
    CloseHandle(Handle)
  else begin
    RaiseLastWin32Error;
    Result := False;
  end;
end;

function ContainsOnlyValidFilenameChars (const s: string) : boolean;
const 
  cValidFilenameChars: tSysCharSet = ['A'..'Z', '0'..'9', 'a'..'z', . . .];
var
  i : integer;
begin
  i := Length (s);
  while (i > 0) and (s [i] in cValidFilenameChars) do
        dec (i);
  result := (s <> '') and (i < 1);
end;

procedure TForm1.Button1Click(Sender: TObject);
const
  sInvalid='/\?*:<>|"' ;
var
  iRet : integer ;
  sFile: string ;
begin
  sFile:=edit1.text ;
  iRet:=LastDelimiter(sInvalid,sFile) ;
  if iRet>0 then
    begin
    Caption:=format('invalid at %d',[iRet]) ;
    end
  else
    Caption:='Vaild file name' ;
end;