写入文件

procedure TForm1.Button1Click(Sender: TObject);
var   F:TextFile;
      fName:string;
begin
    fName:='error.txt';
    AssignFile(F,fName);

    if FileExists(fName)  then Append(F)  else Rewrite(F);

    Writeln(F,'this is string');
    CloseFile(F);
end;