当使用DataContractJsonSerializer
反序列化JSON时,如果输入中有选项卡(格式化JSON),则序列化程序会抛出异常(如下所示).如果我用""替换所有空格,制表符和换行符,则序列化程序可以将其反序列化.
这是怎么回事?
System.MemberAccessException: Cannot create an abstract class.
at System.Runtime.Serialization.FormatterServices.nativeGetUninitializedObject(RuntimeType type)
at System.Runtime.Serialization.FormatterServices.GetUninitializedObject(Type type)
at System.Runtime.Serialization.XmlFormatReaderGenerator.UnsafeGetUninitializedObject(Int32 id)
at ReadBaseSearchElementFromJson(XmlReaderDelegator , XmlObjectSerializerReadContextComplexJson , XmlDictionaryString , XmlDictionaryString[] )
at System.Runtime.Serialization.Json.JsonClassDataContract.ReadJsonValueCore(XmlReaderDelegator jsonReader, XmlObjectSerializerReadContextComplexJson context)
at System.Runtime.Serialization.Json.JsonDataContract.ReadJsonValue(XmlReaderDelegator jsonReader, XmlObjectSerializerReadContextComplexJson context)
at System.Runtime.Serialization.Json.XmlObjectSerializerReadContextComplexJson.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
at ReadSearchElementsFromJson(XmlReaderDelegator , XmlObjectSerializerReadContextComplexJson , XmlDictionaryString , XmlDictionaryString , CollectionDataContract )
at System.Runtime.Serialization.Json.JsonCollectionDataContract.ReadJsonValueCore(XmlReaderDelegator jsonReader, XmlObjectSerializerReadContextComplexJson context)
at System.Runtime.Serialization.Json.JsonDataContract.ReadJsonValue(XmlReaderDelegator jsonReader, XmlObjectSerializerReadContextComplexJson context)
at System.Runtime.Serialization.Json.XmlObjectSerializerReadContextComplexJson.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
at ReadSearchGroupFromJson(XmlReaderDelegator , XmlObjectSerializerReadContextComplexJson , XmlDictionaryString , XmlDictionaryString[] )
at System.Runtime.Serialization.Json.JsonClassDataContract.ReadJsonValueCore(XmlReaderDelegator jsonReader, XmlObjectSerializerReadContextComplexJson context)
at System.Runtime.Serialization.Json.JsonDataContract.ReadJsonValue(XmlReaderDelegator jsonReader, XmlObjectSerializerReadContextComplexJson context)
at System.Runtime.Serialization.Json.XmlObjectSerializerReadContextComplexJson.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Type declaredType, DataContract dataContract, String name, String ns)
at System.Runtime.Serialization.Json.DataContractJsonSerializer.InternalReadObject(XmlReaderDelegator xmlReader, Boolean verifyObjectName)
at System.Runtime.Serialization.XmlObjectSerializer.InternalReadObject(XmlReaderDelegator reader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
at System.Runtime.Serialization.Json.DataContractJsonSerializer.ReadObject(XmlDictionaryReader reader)
at System.Runtime.Serialization.Json.DataContractJsonSerializer.ReadObject(Stream stream)
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这不会反序列化,抛出上面的异常.
{
"Mode":"And",
"Elements":
[
{
"Name":"ID",
"Operator":"Equal",
"Value":"3"
}
]
}
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这确实反序列化.
{"Mode":"And","Elements":[{"Name":"ID","Operator":"Equal","Value":"3"}]}
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我提出了一个展示这个问题的示例解决方案.
您的大部分格式实际上都很好。{
和之间不能有任何空格"__type"
。
请参阅之前的答案:使用 DataContractJsonSerializer 将 JSON 反序列化为抽象列表
例如,您的示例代码尝试反序列化此 JSON 字符串:
"{\r\n\t\"Mode\":\"And\",\r\n\t\"Elements\":\r\n\t[\r\n\t\t{\r\n\t\t\t\"__type\":\"SearchParameter:#JsonTest.Search\",\r\n\t\t\t\"Name\":\"LastName\",\r\n\t\t\t\"Operator\":\"Equal\",\r\n\t\t\t\"Value\":\"Smith\"\r\n\t\t},\r\n\t\t{\r\n\t\t\t\"__type\":\"SearchGroup:#JsonTest.Search\",\r\n\t\t\t\"Mode\":\"Or\",\r\n\t\t\t\"Elements\":\r\n\t\t\t[\r\n\t\t\t\t{\r\n\t\t\t\t\t\"__type\":\"SearchParameter:#JsonTest.Search\",\r\n\t\t\t\t\t\"Name\":\"FirstName\",\r\n\t\t\t\t\t\"Operator\":\"Equal\",\r\n\t\t\t\t\t\"Value\":\"Tim\"\r\n\t\t\t\t},\r\n\t\t\t\t{\r\n\t\t\t\t\t\"__type\":\"SearchParameter:#JsonTest.Search\",\r\n\t\t\t\t\t\"Name\":\"FirstName\",\r\n\t\t\t\t\t\"Operator\":\"Equal\",\r\n\t\t\t\t\t\"Value\":\"Tom\"\r\n\t\t\t\t}\r\n\t\t\t]\r\n\t\t}\r\n\t]\r\n}"
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格式化:
{
"Mode":"And",
"Elements":
[
{
"__type":"SearchParameter:#JsonTest.Search",
"Name":"LastName",
"Operator":"Equal",
"Value":"Smith"
},
{
"__type":"SearchGroup:#JsonTest.Search",
"Mode":"Or",
"Elements":
[
{
"__type":"SearchParameter:#JsonTest.Search",
"Name":"FirstName",
"Operator":"Equal",
"Value":"Tim"
},
{
"__type":"SearchParameter:#JsonTest.Search",
"Name":"FirstName",
"Operator":"Equal",
"Value":"Tom"
}
]
}
]
}
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改成这样,错误就消失了:
"{\r\n\t\"Mode\":\"And\",\r\n\t\"Elements\":\r\n\t[\r\n\t\t{\"__type\":\"SearchParameter:#JsonTest.Search\",\r\n\t\t\t\"Name\":\"LastName\",\r\n\t\t\t\"Operator\":\"Equal\",\r\n\t\t\t\"Value\":\"Smith\"\r\n\t\t},\r\n\t\t{\"__type\":\"SearchGroup:#JsonTest.Search\",\r\n\t\t\t\"Mode\":\"Or\",\r\n\t\t\t\"Elements\":\r\n\t\t\t[\r\n\t\t\t\t{\"__type\":\"SearchParameter:#JsonTest.Search\",\r\n\t\t\t\t\t\"Name\":\"FirstName\",\r\n\t\t\t\t\t\"Operator\":\"Equal\",\r\n\t\t\t\t\t\"Value\":\"Tim\"\r\n\t\t\t\t},\r\n\t\t\t\t{\"__type\":\"SearchParameter:#JsonTest.Search\",\r\n\t\t\t\t\t\"Name\":\"FirstName\",\r\n\t\t\t\t\t\"Operator\":\"Equal\",\r\n\t\t\t\t\t\"Value\":\"Tom\"\r\n\t\t\t\t}\r\n\t\t\t]\r\n\t\t}\r\n\t]\r\n}"
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格式化:
{
"Mode":"And",
"Elements":
[
{"__type":"SearchParameter:#JsonTest.Search",
"Name":"LastName",
"Operator":"Equal",
"Value":"Smith"
},
{"__type":"SearchGroup:#JsonTest.Search",
"Mode":"Or",
"Elements":
[
{"__type":"SearchParameter:#JsonTest.Search",
"Name":"FirstName",
"Operator":"Equal",
"Value":"Tim"
},
{"__type":"SearchParameter:#JsonTest.Search",
"Name":"FirstName",
"Operator":"Equal",
"Value":"Tom"
}
]
}
]
}
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