c＃中返回值的类型与ActionScript中的类型不匹配

Question

我有一个Flash应用程序（由AS3提供）和一个服务器应用程序（由c＃提供）。我使用AMF在它们之间发送和获取消息。但是现在我遇到一个问题，我无法将Action类型的值（包含另一个包含两个List值的对象值）返回给ActionSript。

这是C＃程序

public AMFAddressBookResult SyncAddressBook(AMFLogin loginArgs, AMFAddressBook addressBook)
{
    var result = new AMFAddressBookResult(API_ID);

    AMFReceiver[] receivers = null;
    this.GetReceivers(accessKey, out receivers))

    AMFGroup[] groups = null;
    this.GetGroups(accessKey, out groups))

    result.ResultCode = AMFAddressBookResult.Success;
    return result; // here I cannot return because the type doesnot match
}

这是每个类的定义

public class AMFAddressBookResult : AMFResult
{
    public AMFAddressBookResult()
        : this(0)
    {
        this.AddressBook = new AMFAddressBook();
    }

    public AMFAddressBookResult(int apiID)
        : base(apiID)
    {
        this.AddressBook = new AMFAddressBook();
    }

    [DataMember(Name = "addressBook")]
    public AMFAddressBook AddressBook
    { get; set; }

    //this one cannot work too
    //private AMFAddressBook m_AddressBook;
    //[DataMember(Name = "addressBook")]
    //public AMFAddressBook AddressBook
    //{
    //    get
    //    {
    //        return m_AddressBook;
    //    }
    //    set
    //    {
    //        m_AddressBook = new AMFAddressBook();
    //    }
    //}

}

public class AMFAddressBook
{
    public AMFAddressBook()
    {
        this.m_Receivers = new List<AMFReceiver>();
        this.m_Groups = new List<AMFGroup>();
    }

    private List<AMFReceiver> m_Receivers;
    [DataMember(Name = "receiverList")]
    public AMFReceiver[] Receivers
    {
        get
        {
            return m_Receivers.ToArray();
        }
        set
        {
            m_Receivers = new List<AMFReceiver>(value);
        }
    }
    private List<AMFGroup> m_Groups;
    [DataMember(Name = "groupList")]
    public AMFGroup[] Groups
    {
        get
        {
            return m_Groups.ToArray();
        }
        set
        {
            m_Groups = new List<AMFGroup>(value);
        }
    }
}

并且在ActionScript中，上面的方法应该返回到接受对象类型的方法：

private function onCallSyncAddressBook( result:Object ):void

当然我已经定义了每个匹配c＃类的类，如AMFAddressBook，AMFAddressBookResult，AMFGroup，AMFReceiver ....在ActionScript中

我想知道为什么c＃方法无法返回ActionScript，如果是因为类型不匹配。