1、先定一个DataTable

  private DataTable dtComp
        {
            get
            {
                return this["dtComp"] as DataTable;
            }
            set
            {
                this["dtComp"] = value;
            }
        }

2、创建datatable的行

                    dtComp = new DataTable();
                    dtComp.Columns.Add("SN", typeof(string));
                    dtComp.Columns.Add("Tag", typeof(string));                        

3、往datatable里面写入数据

                        DataRow drCompDataInput = dtComp.NewRow();
                        drCompDataInput["SN"] = lotDataTag.Lot;
                        drCompDataInput["Tag"] = lotDataTag.Tag;
                        dtComp.Rows.Add(drCompDataInput);          

4、比较数据，返回结果为1，就代表有这个数据，正确。如果范围结果不为1，就代表没有找到该数据，则报错

                            if (dtComp.Select("SN ='" + lotData.Lot + "' and Tag = '" + lotData.Tag + "' ").Length != 1)
                            {
                                throw new Exception(TextMessage.Error.T00747(""));
                            }