Question

我对我的SQL服务器返回的错误感到非常困惑 - 这会导致什么原因？

我正在运行的C＃代码是：

List<CalendarEvent> events = new List<CalendarEvent>();
        var db = Database.Open("myDatabase");
        string username = HttpContext.Current.Request.Cookies.Get("username").Value;
        var listOfGroups = db.Query("SELECT GroupID FROM Membership WHERE UserID = (SELECT UserID from Users WHERE Username = @0 )",  username);

        foreach(var groupID in listOfGroups)
            {
                var result = db.Query(
                    @"SELECT e.event_id, e.title, e.description, e.event_start, e.event_end, e.group_id, e.recurring
                    FROM   event e
                    JOIN   Membership m ON m.GroupID = e.group_id
                    WHERE  e.recurring = 0
                    AND    m.GroupID = @0
                    AND    e.event_start >= @1
                    AND    e.event_end <= @2
                    UNION ALL
                    SELECT e.event_id, e.title, e.description, DATEADD(week, w.weeks, e.event_start), DATEADD(week, w.weeks, e.event_end), e.group_id, e.recurring
                    FROM   event e
                JOIN   Membership m ON m.GroupID = e.group_id
                CROSS JOIN 
                    ( SELECT  row_number() OVER (ORDER BY Object_ID) AS weeks
                    FROM SYS.OBJECTS
                    ) AS w
                    WHERE  e.recurring = 1
                    AND    m.GroupID = $3
                    AND    e.event_start >= @4
                    AND    e.event_end <= @5", groupID, start, end, groupID, start, end
                );
                foreach(var record in result)
                    {
                            CalendarEvent cevent = new CalendarEvent();
                            cevent.id = record.event_id;
                            cevent.title = record.title;
                            cevent.description = record.description;
                            cevent.start = record.event_start;
                            cevent.end = record.event_end;
                            cevent.recurring = record.recurring;
                            events.Add(cevent);
                    }
            }
        return events;
}

错误：

异常详细信息：System.ArgumentException：不存在映射对象类型WebMatrix.Data.DynamicRecord到已知的托管提供程序本地类型。

可能导致此问题的原因以及如何解决？

我想要做的是返回所有重复出现的事件= 0，以及任何重复出现的事件= 1我希望在本周和之后的52周内返回。

Answer 1

您的问题与groupID输入参数相符。

var listOfGroups = db.Query("SELECT GroupID FROM Membership WHERE UserID = (SELECT UserID from Users WHERE Username = @0 )",  username);

您的listOfGroups将作为WebMatrix.Data.DynamicRecord个对象的集合返回。您似乎只想要int值，因为您在groupID语句中得到foreach(var groupID in listOfGroups)。

尝试替换最后一行：

AND    e.event_end <= @5", groupID, start, end, groupID, start, end

使用：

AND    e.event_end <= @5", (int)groupID.GroupID, start, end, (int)groupID.GroupID, start, end

这应该从每个动态查询结果的第一个（也是唯一的）列中提取值，该值是您之后的int组ID。

编辑：更正了DynamicRecord查询结果的值调用语法。

从对象类型WebMatrix.Data.DynamicRecord到已知的托管提供程序本机类型不存在映射

1 个答案: