2
抓住這個Linq查詢的頭。它是實體框架。該查詢將轉換爲不同的模型對象。如果我評論或刪除了我指出的導致linq查詢出錯的代碼區域。但在我看來，我應該能夠寫出這樣的查詢與出現此錯誤：Linq to EF系統不支持異常System.NotSupportedException
無法創建類型'DomainModel.Model.CustomerAddress'的空常量值。在此上下文中僅支持實體類型，枚舉類型或基本類型。
任何人都可以告訴我爲什麼我不能或者更重要的是我需要改變以使其工作嗎？
感謝
var orders = from o in _db.Orders
.Include("User")
.Include("OrderItems.Inventories.Product")
.Include("Transactions")
.Include("CustomerAddressBilling.Address")
.Include("CustomerAddressBilling.Customer")
.Include("CustomerAddressBilling.Contact")
.Include("CustomerAddressShipping.Address")
.Include("CustomerAddressShipping.Customer")
.Include("CustomerAddressShipping.Contact")
.Include("ShippingMethod")
// this works ok
let items = (o.OrderItems.Select(i => new Model.OrderItem
{
OrderItemId = i.OrderItemId,
OrderId = i.OrderId,
DateAdded = i.CreateDate,
LineItemPrice = i.Inventories.Sum(ii => ii.Product.Price),
Product = i.Inventories.FirstOrDefault().Product,
Quantity = i.Inventories.Count()
}))
// this works ok
let transactions = (o.Transactions.Select(t => new Model.Transaction
{
Id = t.TransactionId,
OrderId = t.OrderId,
Amount = t.Amount,
AuthorizationCode = t.AuthorizationCode,
DateExecuted = t.TransactionDate,
Notes = t.Notes,
Processor = (Model.TransactionProcessor)t.ProcessorId
}))
// this causes the error
let cab = o.CustAddBillingId.HasValue ? (new Model.CustomerAddress
{
Id = o.CustomerAddressBilling.CustAddId,
UserName = o.User.UserName,
FirstName = o.CustomerAddressBilling.Customer.FirstName,
LastName = o.CustomerAddressBilling.Customer.LastName,
MiddleInitial = o.CustomerAddressBilling.Customer.MiddleName,
Salutation = o.CustomerAddressBilling.Customer.Salutation,
Suffix = o.CustomerAddressBilling.Customer.Suffix,
Street1 = o.CustomerAddressBilling.Address.Line1,
Street2 = o.CustomerAddressBilling.Address.Line2,
Street3 = o.CustomerAddressBilling.Address.Line3,
City = o.CustomerAddressBilling.Address.City,
StateOrProvince = o.CustomerAddressBilling.Address.State,
Zip = o.CustomerAddressBilling.Address.PostalCode,
Country = o.CustomerAddressBilling.Address.Country,
Latitude = o.CustomerAddressBilling.Address.Lat,
Longitude = o.CustomerAddressBilling.Address.Long,
Email = o.CustomerAddressBilling.Contact.ContactInfo,
IsDefault = o.CustomerAddressBilling.IsPrimary
}) : default(Model.CustomerAddress)
// this causes the error
let cas = o.CustAddShippingId.HasValue ? (new Model.CustomerAddress
{
Id = o.CustomerAddressShipping.CustAddId,
UserName = o.User.UserName,
FirstName = o.CustomerAddressShipping.Customer.FirstName,
LastName = o.CustomerAddressShipping.Customer.LastName,
MiddleInitial = o.CustomerAddressShipping.Customer.MiddleName,
Salutation = o.CustomerAddressShipping.Customer.Salutation,
Suffix = o.CustomerAddressShipping.Customer.Suffix,
Street1 = o.CustomerAddressShipping.Address.Line1,
Street2 = o.CustomerAddressShipping.Address.Line2,
Street3 = o.CustomerAddressShipping.Address.Line3,
City = o.CustomerAddressShipping.Address.City,
StateOrProvince = o.CustomerAddressShipping.Address.State,
Zip = o.CustomerAddressShipping.Address.PostalCode,
Country = o.CustomerAddressShipping.Address.Country,
Latitude = o.CustomerAddressShipping.Address.Lat,
Longitude = o.CustomerAddressShipping.Address.Long,
Email = o.CustomerAddressShipping.Contact.ContactInfo,
IsDefault = o.CustomerAddressShipping.IsPrimary
}) : default(Model.CustomerAddress)
// this causes the error
let sm = o.ShippingMethodId.HasValue ? (new ShippingMethod
{
Id = o.ShippingMethod.ShippingMethodId,
Carrier = o.ShippingMethod.Carrier,
ServiceName = o.ShippingMethod.ServiceName,
BaseRate = o.ShippingMethod.BaseRate,
RatePerPound = o.ShippingMethod.RatePerPound,
DaysToDeliver = o.ShippingMethod.DaysToDeliver,
EstimatedDelivery = o.ShippingMethod.EstimatedDelivery
}) : default(ShippingMethod)
select new Model.Order
{
Id = o.OrderId,
UserName = o.User.UserName,
DateCreated = o.CreateDate,
Items = items.AsQueryable(),
Transactions = transactions.AsQueryable(),
ShippingAddressId = o.CustAddShippingId,
BillingAddressId = o.CustAddBillingId,
// have to comment these next 3 lines as well
ShippingAddress = cas,
BillingAddress = cab,
ShippingMethod = sm,
// to here
UserLanguageCode = "en",
DateShipped = o.ShippedDate,
EstimatedDelivery = o.EstimatedDelivery,
TrackingNumber = o.TrackingNumber,
TaxAmount = o.TaxAmount,
DiscountReason = o.DiscountReason,
DiscountAmount = o.DiscountAmount
};
嘗試用'null'代替'default（Model.CustomerAddress）' – 2013-04-08 09:36:26
這樣做，沒關係。我認爲這與cab，cas和sm是對單個對象的引用而不是對集合的引用有關。 – 2013-04-08 15:03:16
有朋友建議這個錯誤是由於let子句中的三元表達式引起的。但我無法弄清楚如何擺脫它。 – 2013-04-10 18:09:12