返回具有導航對象集合的對象時的序列化問題

Question

我正在使用WCF WebAPI創建REST服務和EF4。而返回其具有NavigationProperty一個對象（PO​​CO類的），我得到以下序列化異常：

無法序列類型System.Collections.Generic.ICollection`1 [[模型的構件Models.Customer.Orders。 Order，Models，Version = 1.0.0.0，Culture = neutral，PublicKeyToken = null]]，因爲它是一個接口。

以下是POCO類

[Serializable] 
[DataContract(IsReference = true)] 
[KnownType(typeof(Order))] 
public partial class Customer 
{ 
    #region Primitive Properties 
    [DataMember] 
    public virtual int CustomerID { get; set; } 

    [DataMember] 
    public virtual string CustomerCode { get; set; } 

    [DataMember] 
    public virtual string Description { get; set; } 

    [DataMember] 
    public virtual string Comments { get; set; } 

    [DataMember] 
    public virtual bool DeleteFlag { get; set; } 

    [DataMember] 
    public virtual byte[] RowVersion { get; set; } 
    #endregion 
    #region Navigation Properties 

    [DataMember] 
    public virtual ICollection<Order> Orders 
    { 
     get 
     { 
      if (_order == null) 
      { 
       var newCollection = new FixupCollection<Order>(); 
       newCollection.CollectionChanged += FixupOrders; 
       _order = newCollection; 
      } 
      return _order; 
     } 
     set 
     { 
      if (!ReferenceEquals(_order, value)) 
      { 
       var previousValue = _order as FixupCollection<Order>; 
       if (previousValue != null) 
       { 
        previousValue.CollectionChanged -= FixupOrders; 
       } 
       _order = value; 
       var newValue = value as FixupCollection<Order>; 
       if (newValue != null) 
       { 
        newValue.CollectionChanged += FixupOrders; 
       } 
      } 
     } 
    } 
    private ICollection<Order> _order; 

    #endregion 
    #region Association Fixup 

    private void FixupOrders(object sender, NotifyCollectionChangedEventArgs e) 
    { 
     if (e.NewItems != null) 
     { 
      foreach (Order item in e.NewItems) 
      { 
       item.Customer = this; 
      } 
     } 

     if (e.OldItems != null) 
     { 
      foreach (Order item in e.OldItems) 
      { 
       if (ReferenceEquals(item.Customer, this)) 
       { 
        item.Customer = null; 
       } 
      } 
     } 
    } 

    #endregion 
} 

服務的方法如下：

[WebGet(UriTemplate = "Customer", 
     RequestFormat = WebMessageFormat.Xml, 
     ResponseFormat = WebMessageFormat.Xml)] 
public List<Customer> Get() 
{ 
    CustEntities context = new CustEntities(); 
    return context.Customer.Include("Orders").ToList(); 
} 

在上述方面的任何幫助，是非常可觀的。

感謝

Answer 1

我不認爲你可以序列化屬性在這樣的接口，否則解串器不知道當對象序列化，以創造出具體類型。

您是否可以將ICollection物業更改爲List<T>等具體類型？