请教，怎么取得 output 参数的返回值，谢谢！

Question

create  procedure   ProcJudgeIsEmployyee
@EmployyeeId        varchar(50),
@JudgeIsEmployyee   varchar(50)   output
as
     if   exists(select * from   EmployyeeRecordTable   where  EmployyeeId=@EmployyeeId)
          begin
          set   @JudgeIsEmployyee='是'
          end
     else
          begin
          set   @JudgeIsEmployyee='否' 
          end 
DELPHI  这样调用：
DataModuleForm.ADOStoredProc1.Close;
          DataModuleForm.ADOStoredProc1.ProcedureName:='ProcJudgeIsEmployyee';
          DataModuleForm.ADOStoredProc1.Parameters.Clear;
          DataModuleForm.ADOStoredProc1.Parameters.CreateParameter('@EmployyeeId',ftstring,pdinput,50,trim(edit2.Text));
          DataModuleForm.ADOStoredProc1.Parameters.CreateParameter('@JudgeIsEmployyee',ftstring,pdoutput,50,NULL);
          DataModuleForm.ADOStoredProc1.Prepared:=true;
          DataModuleForm.ADOStoredProc1.ExecProc;
          if     DataModuleForm.ADOStoredProc1.Fieldbyname('@JudgeIsEmployyee').AsString='是'   then          begin
          showmessage('此用户在员工表中');
          exit;          end
          else
          begin
          showmessage('此用户不在员工表中');
          exit;
          end;
可是出现如下的错误：project gamesys.exe raised exception class edatabaseeror with message
'adostoredproc1:field '@JudgeIsEmployyee' not found'
我是错在哪里呢？谢谢各位大哥！

Answer 1

if DataModuleForm.ADOStoredProc1.Fieldbyname('@JudgeIsEmployyee').AsString='是' then
改成
if DataModuleForm.ADOStoredProc1.Params.ParamByName('@JudgeIsEmployyee').Value = '是' then

Answer 2

duanhai 大哥，谢谢！
再请教 duanhai 大哥，
 DataModuleForm.ADOStoredProc1.Parameters.CreateParameter('@JudgeIsEmployyee',ftstring,pdoutput,50,NULL);是不是一般都是 赋 NULL 值啊？谢谢！