Including a Model from different DbContext - entity-framework

Question

I am not sure how to achieve the relation between 2 DbContexts. PurchaseOrderDbContext is a Code first approach & AgencyDbContext is an existing database. How can I include the "Division" from AgencyDbContext based on PurchaseOrder DivisionId?
To start off here is a very simplified version of my code.
Purchase Order Model
namespace Website.Models.PurchaseOrders
{
public class PurchaseOrder
{
public int ID { get; set; }
public DateTime OrderDate { get; set; }
public string Name { get; set; }
public int DivisionId { get; set; }
public int StatusID { get; set; }
public Agency.Division Division { get; set; }
}
}
Division Model (this is in a different DbContext)
namespace Website.Models.Agency
{
public class Division
{
public int DivisionId { get; set; }
public string DivisionName { get; set; }
public string DivisionShortName { get; set; }
public string DivisionAbbrev { get; set; }
public int? DivisionDirectorEmpId { get; set; }
}
}
Agency DbContext
namespace Website.Models.Agency
{
public class AgencyDbContext : DbContext
{
public Agency DbContext(DbContextOptions<AgencyDbContext> options) : base(options)
{
}
public virtual DbSet<Division> Division { get; set; }
public virtual DbSet<Section> Section { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
}
}
}
PurchaseOrderDbContext
namespace Website.Models.PurchaseOrders
{
public class PurchaseOrderDbContext : DbContext
{
public PurchaseOrderDbContext(DbContextOptions<PurchaseOrderDbContext> options) : base(options)
{}
public DbSet<Status> Statuses { get; set; }
public DbSet<PurchaseOrder> PurchaseOrder { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
}
}
}
I get an the error InvalidOperationException: Lambda expression used inside Include is not valid. This is referring to the Include extension on Division.
var purchaseOrder = _context.PurchaseOrder
.Include(p => p.Division)
.Include(p => p.Status)
.OrderByDescending(p => p.OrderDate);
Thank you in advance!

Answer 1

Probably the only way to resolve is to make a query to the first context for items you are looking for, and then populate Division property with entries from second context
public class PurchaseOrderService
{
private readonly PurchaseOrderDbContext purchaseOrderDbContext;
private readonly AgencyDbContext agencyDbContext;
public PurchaseOrderService(PurchaseOrderDbContext purchaseOrderDbContext,
AgencyDbContext agencyDbContext)
{
this.purchaseOrderDbContext = purchaseOrderDbContext;
this.agencyDbContext = agencyDbContext;
}
public PurchaseOrder Get(int id)
{
var purchaseOrder = purchaseOrderDbContext.PurchaseOrder.FirstOrDefault(x => x.ID == id);
if (purchaseOrder == null)
{
return null;
}
purchaseOrder.Division = agencyDbContext.Division.FirstOrDefault(x => x.DivisionId == purchaseOrder.DivisionId);
return purchaseOrder;
}
}