EF上父包含子的SQL查询

Question

I am working on Silverlight with C# using RIA Services - MVVM pattern . When I try to get records from Orders and OrdersDetails I get this error below:

'Notes' is not a member of
'Transient.collection[XXX.SilverLight.Web.Models.OrderDetails(Nullable=True,DefaultValue=)]'.
To extract a property of a collection element, use a subquery to iterate over the collection. Near simple identifier, line 6, column 58.

Here is my query:

public IQueryable<Order> AdvancedSearchOrder(string condition)
{
    ObjectQuery<Order> myQuery = new ObjectQuery<Order>("Orders", DbContext.ObjectContext()).Include("OrderDetails");
    if (condition != "")
    {
        myQuery = myQuery.Where(condition);
    }
    return myQuery;
}

In this case, I have

condition = "( (it.CustomerName like 'test')  )  and  ( (it.OrderDetails.Notes like 'testnote') )";

When I set it to

condition = "( (it.CustomerName like 'test')  )";

then, it works great.

Answer 1

You are trying to use it.OrderDetails as a set, which it likely isn't given that it has a plural name. I'm going to infer that your data model is each Order has one or more OrderDetail records. The list of OrderDetail objects doesn't have a Notes property. An individual OrderDetail does. I'm not sure of the RIA syntax, but it should be something like this:

condition = "( (it.CustomerName like 'test')  )  and  ( 
      (it.OrderDetails.Notes.Any(n => n.Contains('testnote') 
)";