C# 拼接字符串

　　　　　　　　　　　　string[] s_array = Convert.ToString(hsParams[WIP_CUSTCHECK_FIELDS.FIELDS_DEVICENUM]).Split(',');
                    string devicenums = string.Empty;
                    foreach (string s in s_array)
                    {
                        devicenums += "'" + s.Trim() + "',";
                    }
                    if (!string.IsNullOrEmpty(devicenums))
                    {
                        devicenums = devicenums.TrimEnd(',');
                        sqlCommand.AppendFormat(" and t2." + WIP_CUSTCHECK_FIELDS.FIELDS_DEVICENUM + " in ({0})", devicenums);
                    }

 //终检时间
                if (hsParams.ContainsKey(WIP_CUSTCHECK_FIELDS.FIELDS_CREATE_TIME + "1") && hsParams.ContainsKey(WIP_CUSTCHECK_FIELDS.FIELDS_CREATE_TIME + "2"))
                {
                    sqlCommand.AppendFormat(" and t2." + WIP_CUSTCHECK_FIELDS.FIELDS_CREATE_TIME + " between CONVERT(datetime,'{0}') and CONVERT(datetime,'{1}')",
                        Convert.ToString(hsParams[WIP_CUSTCHECK_FIELDS.FIELDS_CREATE_TIME + "1"]),
                        Convert.ToString(hsParams[WIP_CUSTCHECK_FIELDS.FIELDS_CREATE_TIME + "2"]));
                    blCustCheck = true;
                }
                else if (hsParams.ContainsKey(WIP_CUSTCHECK_FIELDS.FIELDS_CREATE_TIME + "1"))
                {
                    sqlCommand.AppendFormat(" and t2." + WIP_CUSTCHECK_FIELDS.FIELDS_CREATE_TIME + ">=CONVERT(datetime,'{0}')", Convert.ToString(hsParams[WIP_CUSTCHECK_FIELDS.FIELDS_CREATE_TIME + "1"]));
                    blCustCheck = true;
                }
                else if (hsParams.ContainsKey(WIP_CUSTCHECK_FIELDS.FIELDS_CREATE_TIME + "2"))
                {
                    sqlCommand.AppendFormat(" and t2." + WIP_CUSTCHECK_FIELDS.FIELDS_CREATE_TIME + "<=CONVERT(datetime,'{0}')", Convert.ToString(hsParams[WIP_CUSTCHECK_FIELDS.FIELDS_CREATE_TIME + "2"]));
                    blCustCheck = true;
                }