序列化自定義主體對象

Question

我有一個自定義主體對象，我希望能夠序列化，以便我可以將其存儲在FormsAuthentication cookie的Userdata中。我試圖使用DataContractJsonSerializer來做到這一點，但當序列化發生時，我只是得到一個空字符串（沒有例外）。

[DataContract] 
public class MyPrincipal : IPrincipal 
{ 
    private readonly MyIdentity _identity; 

    public MyPrincipal(MyIdentity identity) 
    { 
     _identity = identity; 
    } 

    [DataMember] 
    public IIdentity Identity 
    { 
     get { return _identity; } 
     set { } 
    } 

    public bool IsInRole(string role) 
    { 
     return _identity.AuthGroups.Contains(role, StringComparer.OrdinalIgnoreCase); 
    } 

    public bool IsInRole(string[] roles) 
    { 
     return roles.Any(IsInRole); 
    } 
} 

[DataContract] 
public class MyIdentity : IIdentity 
{ 
    private readonly MyCustomData _customData; 

    public MyIdentity(MyCustomData customData) 
    { 
     _customData = customData; 
    } 

    #region IIdentity properties 

    [DataMember] 
    public string Name 
    { 
     get { return Username; } 
     set {} 
    } 

    [DataMember] 
    public string AuthenticationType 
    { 
     get { return "Forms"; } 
     set {} 
    } 

    [DataMember] 
    public bool IsAuthenticated 
    { 
     get { return true; } 
     set { } 
    } 

    #endregion 

    #region custom properties 

    [DataMember] 
    public string FirstName 
    { 
     get { return _customData.FirstName; } 
     set { } 
    } 
    [DataMember] 
    public string LastName 
    { 
     get { return _customData.LastName; } 
     set { } 
    } 
    [DataMember] 
    public string RedwoodID 
    { 
     get { return _customData.CedarnetRedwoodID; } 
     set { } 
    } 
    [DataMember] 
    public string Username 
    { 
     get { return _customData.NetworkLogin; } 
     set { } 
    } 
    [DataMember] 
    public string CuwasTicket 
    { 
     get { return _customData.CuwasTicket; } 
     set { } 
    } 
    [DataMember] 
    public List<string> AuthGroups 
    { 
     get { return _customData.GroupMembership; } 
     set { } 
    } 

    #endregion 
} 

這裏就是我試圖運行到seralize它所有代碼：

var serializer = new DataContractJsonSerializer(typeof(MyPrincipal), new List<Type> {typeof(MyPrincipal), typeof(MyIdentity)}); 
var responseStream = new MemoryStream(); 
serializer.WriteObject(responseStream, user); 
string serializedValue = new StreamReader(responseStream).ReadToEnd(); 

Answer 1

你錯過了一個行：

serializer.WriteObject(responseStream, user); 
responseStream.Position = 0; // This!! 
string serializedValue = new StreamReader(responseStream).ReadToEnd(); 

記住serializer寫入流和StreamReader開始從當前位置流這是流的結束。

在另一張紙條上，系列化IPrincipal和IIdentity看起來不是一件好事。原因是它們代表了一種隨時可能改變的易失性狀態（例如序列化後撤銷權限）。