DataContractJsonSerializer：序列化对象或数组（可以是两者）

Question

I'm accessing the tomtom json api, and the api either returns me an array of objects, or a single object, when an error has happen.

Example:

[{"driverno": "...

Error Example:

{"errorCode": "8011","errorMsg": "request quota reached, error code: 8011"}

The data is accessed WebRequest, WebResponse and they return a stream, which can then be passed to a DataContractJsonSerializer. However, I can't create a serialization class, which accepts both forms of JSON, and the stream can't be passed twice, because the seek function is not supported.

Is there a way, to create a serialization class which supports both types of JSON input?

Answer 1

I found a workaround, where I copy the Stream to a MemoryStream , which enables seeking. I'm not completly settisfied with th solution, becuase it does a Stream copying and the DataContractJsonSerializer twice.

Sample:

string text = File.ReadAllText(PAHT);
text  = Regex.Replace(text, "\\{[\\n\\r ]*\"__type", "{\"__type");

// copy to MemoryStream
using (MemoryStream dataStream = new MemoryStream(Encoding.UTF8.GetBytes(text)))
{
    DataContractJsonSerializer errorDeserializer = new DataContractJsonSerializer(typeof(RequestError));
    RequestError errorSerilaized = (RequestError)errorDeserializer.ReadObject(dataStream);

    // check if an error happened
    if (errorSerilaized.errorCode == null)
    {
        // seek the stream to position 0
        dataStream.Position = 0;

        DataContractJsonSerializer _deserializer = new DataContractJsonSerializer(typeof(NoneErrorSerializationClass));
        NoneErrorSerializationClass tripReportsSerialized = (NoneErrorSerializationClass)_deserializer.ReadObject(dataStream);

        // ...
    }
    else
    {
        MessageBox.Show(errorSerilaized.errorMsg);
    }
}