Как объединить таблицы из нескольких dbcontexts в одну ViewModel?

Итак, у меня есть два dbcontexts для получения данных из разных таблиц, и я хочу объединить их в ViewModel. Я знаю, что мне, вероятно, следует использовать .Join(), но мне было интересно, возможно ли что-то подобное:

Мой контроллер:

public class HomeController : Controller
{
    private readonly NAV_FS_DBContext _navContext;
    private readonly DostebaPpsContext _baseDataContext;

    public HomeController(NAV_FS_DBContext navContext, DostebaPpsContext baseDataContext)
    {
        _navContext = navContext;
        _baseDataContext = baseDataContext;
    }

    // GET: Home
    public async Task<IActionResult> Index()
    {
        List<SpeweSalesLine> speweSalesList = await _navContext.SpeweSalesLines.ToListAsync();
        List<SpeweProdOrderLine> spewePoList = await _navContext.SpeweProdOrderLines.ToListAsync();
        List<Variable> baseDataList = await _baseDataContext.Variables.ToListAsync();
        List<PoItemViewModel> poItems = await _navContext.SpeweProductionOrder
            .Select(x => new PoItemViewModel
            {
                Status = x.Status,
                PONr = x.No,
                ItemNr = x.SourceNo,
                FormType = x.Description,
                Quantity = x.Quantity,
                StartingDate = x.StartingDate,
                EndingDate = x.EndingDate,
                ShipmentDate = speweSalesList.Where(y => y.No == x.No).Select(y => y.ShipmentDate).FirstOrDefault(),
                Priority = spewePoList.Where(y => y.ProdOrderNo == x.No).Select(y => y.Priority).FirstOrDefault(),
                Molds = baseDataList.Where(y => y.SourceNo == x.SourceNo).Select(y => y.MoldPerDay).FirstOrDefault()
            }).ToListAsync();

        return View(poItems);
    }
}

Модель представления:

public class PoItemViewModel
{
    public string? ItemNr { get; set; }
    public int? Status { get; set; }
    public string? FormType { get; set; }
    public decimal? Quantity { get; set; }
    public int? Molds { get; set; }
    public decimal? Days { get; set; }
    public string? PONr { get; set; }
    public DateTime? StartingDate { get; set; }
    public DateTime? EndingDate { get; set; }
    public DateTime? ShipmentDate { get; set; }
    public int? Priority { get; set; }
}

NAV_FS_DBКонтекст:

public partial class NAV_FS_DBContext : DbContext
{
    public NAV_FS_DBContext()
    {
    }

    public NAV_FS_DBContext(DbContextOptions<NAV_FS_DBContext> options)
        : base(options)
    {
    }

    public virtual DbSet<SpeweItem> SpeweItem { get; set; }
    public virtual DbSet<SpeweProductionOrder> SpeweProductionOrder { get; set; }

    public virtual DbSet<SpeweItemLedgerEntry> SpeweItemLedgerEntries { get; set; }

    public virtual DbSet<SpeweSalesLine> SpeweSalesLines { get; set; }

    public virtual DbSet<SpeweValueEntry> SpeweValueEntries { get; set; }
    public virtual DbSet<SpeweProdOrderLine> SpeweProdOrderLines { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        => optionsBuilder.UseSqlServer("Name=ConnectionStrings:CS2");

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.UseCollation("Latin1_General_100_CI_AS");

        modelBuilder.Entity<SpeweItem>(entity =>
        {
            entity.HasKey(e => e.No).HasName("SPEWE$Item$0");

            entity.ToTable("SPEWE$Item", "dbo");
            //etc...
            });
            OnModelCreatingPartial(modelBuilder);
        }

        partial void OnModelCreatingPartial(ModelBuilder modelBuilder);
    }
}

Модель SpeweProductionOrder (из dbcontext):

public partial class SpeweProductionOrder
{
    public byte[] Timestamp { get; set; } = null!;

    public int Status { get; set; }

    public string No { get; set; } = null!;

    public string Description { get; set; } = null!;

    public string SearchDescription { get; set; } = null!;

    public string Description2 { get; set; } = null!;

    public DateTime CreationDate { get; set; }

    public DateTime LastDateModified { get; set; }

    public int SourceType { get; set; }

    public string SourceNo { get; set; } = null!;

    public string RoutingNo { get; set; } = null!;

    public string InventoryPostingGroup { get; set; } = null!;

    public string GenProdPostingGroup { get; set; } = null!;

    public string GenBusPostingGroup { get; set; } = null!;

    public DateTime StartingTime { get; set; }

    public DateTime StartingDate { get; set; }

    public DateTime EndingTime { get; set; }

    public DateTime EndingDate { get; set; }

    public DateTime DueDate { get; set; }

    public DateTime FinishedDate { get; set; }

    public byte Blocked { get; set; }

    public string ShortcutDimension1Code { get; set; } = null!;

    public string ShortcutDimension2Code { get; set; } = null!;

    public string LocationCode { get; set; } = null!;

    public string BinCode { get; set; } = null!;

    public string ReplanRefNo { get; set; } = null!;

    public int ReplanRefStatus { get; set; }

    public int LowLevelCode { get; set; }

    public decimal Quantity { get; set; }

    public decimal UnitCost { get; set; }

    public decimal CostAmount { get; set; }

    public string NoSeries { get; set; } = null!;

    public string PlannedOrderNo { get; set; } = null!;

    public string FirmPlannedOrderNo { get; set; } = null!;

    public string SimulatedOrderNo { get; set; } = null!;

    public DateTime StartingDateTime { get; set; }

    public DateTime EndingDateTime { get; set; }

    public int DimensionSetId { get; set; }

    //etc...
}

Модель SpeweSalesLine (из dbcontext):

public partial class SpeweSalesLine
{
    public byte[] Timestamp { get; set; } = null!;

    public int DocumentType { get; set; }

    public string DocumentNo { get; set; } = null!;

    public int LineNo { get; set; }

    public string SellToCustomerNo { get; set; } = null!;

    public int Type { get; set; }

    public string No { get; set; } = null!;

    public string LocationCode { get; set; } = null!;

    public string PostingGroup { get; set; } = null!;

    public DateTime ShipmentDate { get; set; }

    public string Description { get; set; } = null!;

    public string Description2 { get; set; } = null!;

    public string UnitOfMeasure { get; set; } = null!;

    public decimal Quantity { get; set; }

    public decimal OutstandingQuantity { get; set; }

    public decimal QtyToInvoice { get; set; }

    public decimal QtyToShip { get; set; }

    public decimal UnitPrice { get; set; }

    public decimal UnitCostLcy { get; set; }

    public decimal Vat { get; set; }

    public decimal LineDiscount { get; set; }

    public decimal LineDiscountAmount { get; set; }

    public decimal Amount { get; set; }

    public decimal AmountIncludingVat { get; set; }

    public byte AllowInvoiceDisc { get; set; }

    public decimal GrossWeight { get; set; }

    public decimal NetWeight { get; set; }

    public decimal UnitsPerParcel { get; set; }

    public decimal UnitVolume { get; set; }

    public int ApplToItemEntry { get; set; }

    public string ShortcutDimension1Code { get; set; } = null!;

    public string ShortcutDimension2Code { get; set; } = null!;

    public string CustomerPriceGroup { get; set; } = null!;

    public string JobNo { get; set; } = null!;

    public string WorkTypeCode { get; set; } = null!;

    public byte RecalculateInvoiceDisc { get; set; }

    public decimal OutstandingAmount { get; set; }

    public decimal QtyShippedNotInvoiced { get; set; }

    public decimal ShippedNotInvoiced { get; set; }

    public decimal QuantityShipped { get; set; }

    public decimal QuantityInvoiced { get; set; }

    public string ShipmentNo { get; set; } = null!;

    public int ShipmentLineNo { get; set; }

    public decimal Profit { get; set; }

    public string BillToCustomerNo { get; set; } = null!;

    public decimal InvDiscountAmount { get; set; }

    public string PurchaseOrderNo { get; set; } = null!;

    public int PurchOrderLineNo { get; set; }

    public byte DropShipment { get; set; }

    public string GenBusPostingGroup { get; set; } = null!;

    public string GenProdPostingGroup { get; set; } = null!;

    public int VatCalculationType { get; set; }

    public string TransactionType { get; set; } = null!;

    public string TransportMethod { get; set; } = null!;

    public int AttachedToLineNo { get; set; }

    public string ExitPoint { get; set; } = null!;

    public string Area { get; set; } = null!;

    public string TransactionSpecification { get; set; } = null!;

    public string TaxCategory { get; set; } = null!;

    public string TaxAreaCode { get; set; } = null!;

    public byte TaxLiable { get; set; }

    public string TaxGroupCode { get; set; } = null!;

    public string VatClauseCode { get; set; } = null!;

    public string VatBusPostingGroup { get; set; } = null!;

    public string VatProdPostingGroup { get; set; } = null!;

    public string CurrencyCode { get; set; } = null!;

    public decimal OutstandingAmountLcy { get; set; }

    public decimal ShippedNotInvoicedLcy { get; set; }

    public int Reserve { get; set; }

    public string BlanketOrderNo { get; set; } = null!;

    public int BlanketOrderLineNo { get; set; }

    public decimal VatBaseAmount { get; set; }

    public decimal UnitCost { get; set; }

    public byte SystemCreatedEntry { get; set; }

    public decimal LineAmount { get; set; }

    public decimal VatDifference { get; set; }

    public decimal InvDiscAmountToInvoice { get; set; }

    public string VatIdentifier { get; set; } = null!;

    public int IcPartnerRefType { get; set; }

    public string IcPartnerReference { get; set; } = null!;

    public decimal Prepayment { get; set; }

    public decimal PrepmtLineAmount { get; set; }

    public decimal PrepmtAmtInv { get; set; }

    public decimal PrepmtAmtInclVat { get; set; }

    public decimal PrepaymentAmount { get; set; }

    public decimal PrepmtVatBaseAmt { get; set; }

    public decimal PrepaymentVat { get; set; }

    public int PrepmtVatCalcType { get; set; }

    public string PrepaymentVatIdentifier { get; set; } = null!;

    public string PrepaymentTaxAreaCode { get; set; } = null!;

    public byte PrepaymentTaxLiable { get; set; }

    public string PrepaymentTaxGroupCode { get; set; } = null!;

    public decimal PrepmtAmtToDeduct { get; set; }

    public decimal PrepmtAmtDeducted { get; set; }

    public byte PrepaymentLine { get; set; }

    public decimal PrepmtAmountInvInclVat { get; set; }

    public decimal PrepmtAmountInvLcy { get; set; }

    public string IcPartnerCode { get; set; } = null!;

    public decimal PrepmtVatAmountInvLcy { get; set; }

    public decimal PrepaymentVatDifference { get; set; }

    public decimal PrepmtVatDiffToDeduct { get; set; }

    public decimal PrepmtVatDiffDeducted { get; set; }

    public int DimensionSetId { get; set; }

    public decimal QtyToAssembleToOrder { get; set; }

    public decimal QtyToAsmToOrderBase { get; set; }

    public string JobTaskNo { get; set; } = null!;

    public int JobContractEntryNo { get; set; }

    public string DeferralCode { get; set; } = null!;

    public DateTime ReturnsDeferralStartDate { get; set; }

    //etc...
}

Модель переменной (из dbcontext)

public partial class Variable
{
    public string SourceNo { get; set; } = null!;

    public string Type { get; set; } = null!;

    public int PiecePerPallett { get; set; }

    public int Lotsize { get; set; }

    public int MoldPerDay { get; set; }

    public int FormAmount { get; set; }

    public int CavityAmount { get; set; }

    public decimal FormTime { get; set; }

    public decimal FillTime { get; set; }

    public decimal CarouselRotation { get; set; }

    public decimal CompletionTime { get; set; }

    public decimal Cycle { get; set; }
}

Очевидно, это не работает, поскольку я получаю исключение InvalidOperationException, но я имею в виду, что я заранее загружаю все данные и сохраняю их в виде списка, так почему я не могу получить/сравнить данные, например, из «spewePoList»?

Было бы неплохо узнать некоторые мысли по этому поводу, и заранее благодарю вас за помощь.