Question

一直试图对此进行排序，而且大多数似乎指向使用SingleOrDefault，我不是，但仍然会收到以下错误：

System.Web.HttpUnhandledException (0x80004005)
: Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.InvalidOperationException: Sequence contains more than one element at System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult)
at System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries)
at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query)
at System.Data.Linq.Table`1.System.Linq.IQueryProvider.Execute[TResult](Expression expression)
at System.Linq.Queryable.Any[TSource](IQueryable`1 source, Expression`1 predicate)
at DOAwayFromDesk.GetNextRecord(Int32 user)

这是代码

public AwayFromDesk GetNextRecord(int user) {
   using (Intranet2012DataContext db = DataHelper.GetDataContext()) {
        if (!db.AwayFromDesks.Any(w => w.ownerlinkid == user && w.enddate >= DateTime.Now && w.complete == false))
            return null;

        return (from a in db.AwayFromDesks
                where a.ownerlinkid == user
                      && a.enddate >= DateTime.Now && a.complete == false
                orderby a.startdate , a.enddate
                select a).FirstOrDefault();
    }
}

不确定还要检查什么。

检查了SQL运行的内容，并且每次只返回一条记录。

exec sp_executesql N'SELECT 
(CASE 
    WHEN EXISTS(
        SELECT NULL AS [EMPTY]
        FROM [dbo].[AwayFromDesk] AS [t0]
        WHERE ([t0].[ownerlinkid] = @p0) AND ([t0].[enddate] >= @p1) AND (NOT ([t0].[complete] = 1))
        ) THEN 1
    ELSE 0
 END) AS [value]',N'@p0 int,@p1 datetime',@p0=1,@p1='2014-01-24 08:30:28:877'

exec sp_executesql N'SELECT TOP (1) [t0].[id], [t0].[added], [t0].[ownerlinkid], [t0].[startdate], [t0].[enddate], [t0].[reason], [t0].[contact], [t0].[internalmeeting], [t0].[reminder], [t0].[remindertime], [t0].[recur], [t0].[complete]
FROM [dbo].[AwayFromDesk] AS [t0]
WHERE ([t0].[ownerlinkid] = @p0) AND ([t0].[enddate] >= @p1) AND (NOT ([t0].[complete] = 1))
ORDER BY [t0].[startdate], [t0].[enddate]',N'@p0 int,@p1 datetime',@p0=1,@p1='2014-01-24 08:30:28:890'

我注意到并且有点混乱的是Any正在做这件事

if (!db.AwayFromDesks.Any(w => w.ownerlinkid == user && w.enddate >= DateTime.Now && w.complete == false))
            return null;

但SQL就是这个

exec sp_executesql N'SELECT 
(CASE 
    WHEN EXISTS(
        SELECT NULL AS [EMPTY]
        FROM [dbo].[AwayFromDesk] AS [t0]
        WHERE ([t0].[ownerlinkid] = @p0) AND ([t0].[internalmeeting] = 1) AND (NOT ([t0].[complete] = 1))
        ) THEN 1
    ELSE 0
 END) AS [value]',N'@p0 int',@p0=1

我没有提到我使用的结束日期，但使用的是我在Linq声明中没有使用的internalMeeting，很奇怪。

10 / Feb / 2014 ::现在尝试将.Any更改为.Count，但仍然会随机获取错误。

if (db.vwAwayFromDeskAnyChecks.Count(w => w.ownerlinkid == user && w.enddate >= DateTime.Now)==0) return null;

这甚至是查询：

SELECT COUNT(*) AS [value]
FROM [vwAwayFromDeskAnyCheck] AS [t0]
WHERE ([t0].[ownerlinkid] = @p0) AND ([t0].[enddate] >= @p1)

难倒？不知道这是怎么可能的。

常见的但让我难倒的Sequence包含多个元素，而不是使用SingleOrDefault

0 个答案: