从asp.net中的存储过程中获取返回值

Question

我有一个存储过程

ALTER PROC TESTLOGIN
    @UserName varchar(50),
    @password varchar(50)
As
Begin
    declare @return int;

    set @return  = (SELECT COUNT(*) 
                    FROM CPUser 
                    WHERE UserName = @UserName 
                    AND Password = @password);

    return @return;
End

并在c#

SqlConnection con = db.con;
SqlCommand cmd = new SqlCommand("TESTLOGIN", con);
cmd.CommandType = CommandType.StoredProcedure;

SqlParameter parm = new SqlParameter("@return", SqlDbType.Int);
parm.Direction = ParameterDirection.ReturnValue;

cmd.Parameters.Add(parm);
cmd.Parameters.Add(new SqlParameter("@UserName", txtUserName.Text.ToString().Trim()));
cmd.Parameters.Add(new SqlParameter("@password", txtPassword.Text.ToString().Trim()));

cmd.ExecuteNonQuery();
con.Close();

int id = Convert.ToInt32(parm.Value);

但它总是返回0.请帮我解决这个问题

Answer 1

您需要ParameterDirection.ReturnValue在代码中将Direction设置为参数但不需要在SP中添加额外参数.试试这个

  SqlParameter returnParameter = cmd.Parameters.Add("RetVal", SqlDbType.Int);
  returnParameter.Direction = ParameterDirection.ReturnValue;
  cmd.ExecuteNonQuery();

  int id = (int) returnParameter.Value;