谁帮我看看啊，这个老是返回值为-1，一调试，就叫我重启vs什么问题啊，急求帮助！！

  public int ValidateAdmin(string sql, string adminID,string adminPwd)
        {
            int i;
            try
            {
                this.openCon();
                this.cmd = new SqlCommand(sql, this.con);
                this.cmd.CommandType = CommandType.StoredProcedure;
                SqlParameter[] pars = new SqlParameter[] {
                    new SqlParameter("@AdminID", SqlDbType.VarChar,50),
                    new SqlParameter("@AdminPwd", SqlDbType.VarChar,50)
                };
                pars[0].Value = adminID;
                pars[1].Value = adminPwd;
                foreach (SqlParameter parameter in pars)
                {
                    this.cmd.Parameters.Add(parameter);
                }
                i = (int)this.cmd.ExecuteScalar();
            }
            catch
            {
                i = -1;
            }
            finally
            {
                this.closeCon();
            }
            return i;
        }

        public void openCon()
        {
            if (this.con == null)
            {
                this.con = new SqlConnection(this.strCon);
            }
            if (this.con.State.Equals(ConnectionState.Closed))
            {
                this.con.Open();
            }
        }