小编Joa*_*kim的帖子

List<Post> list =
(
    from c in db.TitleComments
    join t in db.Titles on c.TitleId equals t.Id
    join u in db.Users on c.UserId equals u.Id
    where t.Id == _titleId && c.Date > time
    orderby c.Date descending
    select new Post { Username = u.Username, PostingDate = c.Date.ToString(), Data = c.Comment }
).ToList();

上面的代码导致date转换为string,PostingDate = c.Date.ToString().任何想法如何解决这个问题？

异常错误:{"LINQ to Entities无法识别方法'System.String ToString()'方法,并且此方法无法转换为商店表达式."}

我有两节课:

class Foo{
    public int FooId { get; set; }
    ...
    public Bar Bar { get; set }
}

class Bar{
    public int BarId { get; set; }
    public int FooId { get; set }
    ...
}

当我然后运行这样的查询:

sqlConnection.Query<Foo, Bar, Foo>(
    "SELECT * FROM Foo JOIN Bar ON Foo.FooId = Bar.FooId",
    (foo, bar) => { 
         foo.Bar = bar;
         return foo; 
       }, 
    splitOn: "FooId");

结果将是Foo和Bar上的所有属性都将映射除了Bar.BarId.检查列名并在我的Bar类中键入数据库后,我仍然找不到任何差异.

我偶然发现的一件奇怪的事情是,如果我写道:

"SELECT *, BarId AS BarId FROM Foo JOIN Bar ON Foo.FooId = Bar.FooId"

Bar.BarId实际上按预期映射,我误解了如何使用Dapper或者这是一个错误吗？