强制string.format为查询设置null值

Question

我有这个：

int id = 10;
long partnerId = 20;
long? groupId = null;
DateTime startDate = Datetime.Now.AddDays(-5);
DateTime endDate = Datetime.Now;
bool isTesting = true;
bool isActive = false;
query = @"SELECT Vita as VitalLevel,count(distinct ccrid) as Answers, Vitald as VitalType
                      FROM CORE.vRecipientsc rd
                      INNER JOIN Recipiendy rs ON rs.CRRID = rd.RID
                      INNER JOIN RecipientStungs rsvr ON rsvr.StudyId = rs.Id 
                      WHERE SBURID = {0} 
                      AND ({5} IS null OR {5}=SbuGroupRID)
                      AND rs.DTUTC_Created >= '{1}' 
                      AND rs.DTUTC_Created <= '{2}'
                      AND rsvr.VitalTypeId = 8 
                      AND rsvr.VitalValue <> '' 
                      AND (rd.isTesting = {3} or rd.isTesting = 0)
                      AND rd.IsActive= {4}
                      GROUP BY rsvr.VitalValue, rsvr.VitalLevel, rsvr.VitalTypeId";
String.Format(query, new object[] {
            partnerId, startDate, endDate, Convert.ToInt32(isTesting), Convert.ToInt32(isActive), groupId
        });

然后，我与数据库和执行多个查询有一个连接，但是当我执行查询时，在string.format中替换了空格中的null值，我希望将线直接替换为groupID变量设置为null。我可以使用C＃？

Answer 1

您可以使用string.format方法(String，Object [](和??对于无效的值。

String.Format(query, partnerId, startDate, endDate, Convert.ToInt32(isTesting), Convert.ToInt32(isActive), groupId ?? "null");

，或者您可以使用相同的方法和三元运算符

String.Format(query, new object[] { partnerId, startDate, endDate, Convert.ToInt32(isTesting), Convert.ToInt32(isActive), groupId != null ? groupId.ToString() : "null" });

Answer 2

您可以将行本身用作最后一个参数：

用{5}替换AND ({5} IS null OR {5}=SbuGroupRID)，并将最后一个参数的值设置为groupId.HasValue ? string.Format("AND ({0} IS null OR {0}=SbuGroupRID)", groupId) : string.Empty

您可以在查询字符串之前将其移至另一个变量中，然后将该变量用作最后一个参数。