Linq 到实体参数化构造函数 Datetime

Question

我知道 Linq to entity 不支持参数化构造函数，但是如何做到这一点？:

date = new DateTime(int.Parse(SqlFunctions.StringConvert(l.rok).Trim()), int.Parse(SqlFunctions.StringConvert(l.mesic).Trim()), 1)

整个例子:

var objects = from object in GetObjects()
                   select new MyObject{
                   name = object.name;
                   date = new DateTime(object.rok,object.month,object.day)
                   }

这该怎么做？

Answer 1

使用此处找到的 EntityFunctions CreateDateTime 方法:http://msdn.microsoft.com/en-us/library/system.data.objects.entityfunctions.createdatetime

如该链接的注释中所述，这些辅助方法被构建为转换为 SQL 等效项:

You cannot call this function directly. This function can only appear within a LINQ to Entities query.

This function is translated to a corresponding function in the database.