DevExpress XAF is a framework for .NET and Visual Studio developers who wants to create Office-like LOB apps for desktop, web and mobile faster and without hiring a large team.
Wednesday, December 30, 2015
EF - Use of complex types that are not registered in DbContext and have no key property
I want to highlight a minor usability improvement built into v15.2 for our Entity Framework fans. This is all about a simpler integration of complex types without keys (learn more from EF docs...).
The situation is already pretty much summarized in the Support Center, and here I just want to re-post the main details. To begin with, consider the following EF classes:
[C#]public class Product { public Product() { PriceRange = new Range(); } public Int32 ID { get; set; } public String Name { get; set; } public Range PriceRange { get; set; } } public class Range { public Range() { } public Decimal Low { get; set; } public Decimal High { get; set; } }
public class EFDemoDbContext : DbContext {
...
public DbSet<Product> Products { get; set; }
...
}
Note that the Range class has no key property and Entity Framework does not map this class to a separate database table. By default, properties of such a class persist in the table mapped to the parent Product class, where the Range type property is declared. So, the Product table will have the ID, Name, PriceRange_Low and PriceRange_High columns:
Starting with v15.2.4 we recommend that you apply the ExpandObjectMembers attribute to properties of a complex type:
[C#][ExpandObjectMembers(ExpandObjectMembers.Always)] public Range PriceRange { get; set; }
to be able to view and edit them in the XAF CRUD UI without any additional steps:
Should you require support for other use-case scenarios involving complex types, please let me know via the Support Center or here in comments. Thanks!
P.S.
Happy holidays!
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