在Linq to SQL和Entity Framework，使用Linq查询数据的时候会出现错误：There is already an open DataReader associated with this Command which must be closed first 。解决方案：在数据库连接串上添加MultipleActiveResultSets=true。

在Linq to SQL和Entity Framework，使用Linq查询数据的时候会出现错误：There is already an open DataReader associated with this Command which must be closed first 。

解决方案：

在数据库连接串上添加MultipleActiveResultSets=true。

​​Fixing the "There is already an open DataReader associated with this Command which must be closed first." exception in Entity Framework​​