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ASP.NET派生类型的ScriptService反序列化问题

scriptservice json ajax javascript c#

josh3736 · 技术社区 · 14 年前

我有一个 ScriptService web方法(.NET 3.5),它接受抽象基类型的单个参数:

[WebMethod(EnableSession=true)]
[ScriptMethod()]
public bool Test(Item item) { ... }

以及:

namespace Namespace {
public abstract class Item
{
    public int id;
}

public class Group : Item
{
    public Item[] items;
}

public class Instance : Item
{
    public string whatever;
}
}

item 将是一个 Group 其中包含 Instance 组 物体。我从jQuery调用此服务;我没有使用Microsoft客户端框架。对其他方法的调用工作正常。

问题是: 当我进行调用时,在调用我的方法之前会抛出一个异常。例如,如果我的电话是:

POST /WebService.asmx/Test HTTP/1.1
Content-Type: application/json; charset=UTF-8
Accept: application/json, text/javascript, */*

{"item":{"id":0,"__type":"Namespace.Group","items":[]}}

…我得到一个 InvalidOperationException :

{"Message":"Operation is not valid due to the current state of the object.","StackTrace":"   at System.Web.Script.Serialization.ObjectConverter.ConvertDictionaryToObject(IDictionary`2 dictionary, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object& convertedObject)\r\n   at System.Web.Script.Serialization.ObjectConverter.ConvertObjectToTypeInternal(Object o, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object& convertedObject)\r\n   at System.Web.Script.Serialization.ObjectConverter.ConvertObjectToTypeMain(Object o, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object& convertedObject)\r\n   at System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeInternal(Int32 depth)\r\n   at System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeDictionary(Int32 depth)\r\n   at System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeInternal(Int32 depth)\r\n   at System.Web.Script.Serialization.JavaScriptObjectDeserializer.BasicDeserialize(String input, Int32 depthLimit, JavaScriptSerializer serializer)\r\n   at System.Web.Script.Serialization.JavaScriptSerializer.Deserialize(JavaScriptSerializer serializer, String input, Type type, Int32 depthLimit)\r\n   at System.Web.Script.Serialization.JavaScriptSerializer.Deserialize[T](String input)\r\n   at System.Web.Script.Services.RestHandler.ExecuteWebServiceCall(HttpContext context, WebServiceMethodData methodData)","ExceptionType":"System.InvalidOperationException"}

__type JSON对象的成员或将其更改为 Namespace.Item abstract 修改器来自 Item ),异常会消失,但得到的反序列化对象显然有点无用。

我错过了什么?

2 回复 | 直到 14 年前

Community CDub 7 年前

啊哈!点击这个问题右侧的相关链接,我发现 an answer 帮助我解决了这个问题。

GenerateScriptType 属性必须应用于web服务类:

[WebService( ... )]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[ScriptService]
[GenerateScriptType(typeof(Group))]
[GenerateScriptType(typeof(Instance))]
public class WebService : System.Web.Services.WebService
{
    [WebMethod(EnableSession=true)]
    [ScriptMethod()]
    public bool Test(Item item) { ... }
}

Suraj Rao Raas Masood 6 年前

我可以用 Newtonsofts JsonConvert 如下所示。

[System.Web.Services.WebMethod]      
public static void MyAjaxCallingMethod(object inputs)
    {           
    string stingDataFromAjaxCall = JsonConvert.SerializeObject(inputs);
            MyObject myObj = JsonConvert.DeserializeObject<MyObject>(stingDataFromAjaxCall);
            ....}