linq技巧-通过使用匿名类型来构造一个多属性连接查询表达式

var orders = from o in context.Orders
    join a in context.Accounts on
    // 使用匿名类型来构造一个复合的查询表达式
    new { Id = o.AccountId, City = o.ShipCity, State = o.ShipState }
    equals
    new { Id = a.AccountId, City = a.City, State = a.State }
    select o;