如何使用Json.NET Silverlight中的TypeNameHandling.Objects進行反序列化？

Question

嘗試在Silverlight中反序列化時出現異常。 Test1失敗，而Test2成功。我也嘗試了TypeNameAssemblyFormat對簡單和完整，但得到相同的結果。 Test2可以解析程序集，爲什麼不能Json.NET？

更新：忘了提及我試圖反序列化的類型是在與發生反序列化的silverlight程序集不同的程序集中定義的。

這兩個測試都在非Silverlight .NET應用程序中工作。

如何反序列化具有typenames的json字符串？

private void Test1() 
{ 
    JsonSerializerSettings settings = new JsonSerializerSettings(); 
    settings.TypeNameHandling = TypeNameHandling.Objects; 
    string json1 = "{\"$type\":\"AmberGIS.NetworkTrace.DTO.NTPoint, NetworkTrace.DTO.Assembly\",\"X\":0.0,\"Y\":0.0,\"SpatialReference\":null}"; 
    try 
    { 
     var n1 = JsonConvert.DeserializeObject<NTPoint>(json1, settings); 
     //Error resolving type specified in JSON 'AmberGIS.NetworkTrace.DTO.NTPoint, NetworkTrace.DTO.Assembly'. 
     //Could not load file or assembly 'NetworkTrace.DTO.Assembly, Culture=neutral, PublicKeyToken=null' or one of its dependencies. 
     //The requested assembly version conflicts with what is already bound in the app domain or specified in the manifest. 
     //(Exception from HRESULT: 0x80131053) 
    } 
    catch (Exception ex) 
    { 
     while (ex != null) 
     { 
      Debug.WriteLine(ex.Message); 
      ex = ex.InnerException; 
     } 
    } 
} 

這Test2的成功：

private void Test2() 
{ 
    var pnt1 = new AmberGIS.NetworkTrace.DTO.NTPoint(); 
    Debug.WriteLine(pnt1.GetType().AssemblyQualifiedName); 
    // "AmberGIS.NetworkTrace.DTO.NTPoint, NetworkTrace.DTO.Assembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" 

    string fullName = "AmberGIS.NetworkTrace.DTO.NTPoint, NetworkTrace.DTO.Assembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"; 
    var t = Type.GetType(fullName); 
    var pnt2 = Activator.CreateInstance(t) as NTPoint; 

} 

Answer 1

嘗試增加設置JsonConvert.DeserializeObject<T>(json, Settings)， 這裏設置爲：

new JsonSerializerSettings 
       { 
        TypeNameHandling = TypeNameHandling.Objects, 
        TypeNameAssemblyFormat = System.Runtime.Serialization.Formatters.FormatterAssemblyStyle.Full 
       } 

Answer 2

我通過下載源Json.NET 4.0r2，並加入2行的黑客代碼DefaultSerializationBinder.cs，如下圖所示解決了我的問題。這可能不適用於強命名的程序集。 Silverlight缺少掃描加載程序集的appdomain的方法，請參閱here。

#if !SILVERLIGHT && !PocketPC 
     // look, I don't like using obsolete methods as much as you do but this is the only way 
     // Assembly.Load won't check the GAC for a partial name 
#pragma warning disable 618,612 
     assembly = Assembly.LoadWithPartialName(assemblyName); 
#pragma warning restore 618,612 
#else 
      // **next 2 lines are my hack** ... 
      string fullName = String.Format("{0}, {1}, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null",typeName,assemblyName); 
      return Type.GetType(fullName); 

     assembly = Assembly.Load(assemblyName); 
#endif 

Answer 3

我在這裏發佈我的解決方案，不需要修改Json.NET：

問題在於以下線對於Silverlight來說是不夠的：

string json1 = "{\"$type\":\"AmberGIS.NetworkTrace.DTO.NTPoint, NetworkTrace.DTO.Assembly\" ... }"; 

它的需要：

string json1 = "{\"$type\":\"AmberGIS.NetworkTrace.DTO.NTPoint, NetworkTrace.DTO.Assembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null \", ...}"; 

所以，我包括在JSON（在我的情況下，JSON是不能改變的，因爲它是來自服務器，並沒有因JSON.net生成）的方式是手動

string json = <some json you want fixed> 
Type type = <the target type you want> 
JObject jsonObject = JObject.parse (json); 
jsonObject["$type"] = type.FullName + ", " + type.Assembly.FullName; 
json = jsonObject.ToString(Formatting.None, null); 

然後你就可以反序列化照常使用

JsonSerializerSettings settings = new JsonSerializerSettings { TypeNameHandling = TypeNameHandling.All }; 
var n1 = JsonConvert.DeserializeObject<NTPoint>(json, settings);