Mapping LinqToEntities join to ViewModel

问题

I have the following Models and ViewModels (edited for brevity):

     Order Model:
            OrderId
            ShippingAddressId 
            .....
    Address Model:
            AddressId
            .....
    OrderViewModel:
            Some Property from Order Model and Address Model

how can inner join two tables and map to a viewmodel ?

    var query= from o in ctx.Orders
        join addr in ctx.Addresses
        on o.ShippingAddressId equals addr.AddressId
        select new OrderViewModel.InjectFrom(o)
                              .InjectFrom(addr)
                              as OrderViewModel;

this code doesn't work .

回答1:

You need to first materialize the result with ToList:

var query = (from o in ctx.Orders
             join addr in ctx.Addresses
             on o.ShippingAddressId equals addr.AddressId
             select new { o, addr }
            ).ToList()
             .Select(x => new OrderViewModel().InjectFrom(x.o)
                                              .InjectFrom(x.addr)
                          as OrderViewModel);

来源：https://stackoverflow.com/questions/11988573/mapping-linqtoentities-join-to-viewmodel