CODEWITHSUNDEEP
c#.netjson.net
moswald
moswald

Reputation: 11677

Json.Net fails to serialize to a stream, but works just fine serializing to a string

Internally, JsonConvert.SerializeObject(obj, Formatting.Indented) boils down to

JsonSerializer jsonSerializer = JsonSerializer.Create(null);
StringWriter stringWriter = new StringWriter(new StringBuilder(256), (IFormatProvider) CultureInfo.InvariantCulture);
using (JsonTextWriter jsonTextWriter = new JsonTextWriter((TextWriter) stringWriter))
{
  jsonTextWriter.Formatting = formatting;
  jsonSerializer.Serialize((JsonWriter) jsonTextWriter, value);
}
return stringWriter.ToString();

This works just fine. However, if I do the following:

string json;

JsonSerializer jsonSerializer = JsonSerializer.Create();

using (var stream = new MemoryStream())
using (var streamWriter = new StreamWriter(stream, Encoding.UTF8))
using (var jsonWriter = new JsonTextWriter(streamWriter))
{
    serializer.Serialize(jsonWriter, cmd);

    stream.Position = 0;
    using (var reader = new StreamReader(stream))
    {
        json = reader.ReadToEnd();
    }
}

Then the value of json is "". Can anyone point me to my mistake?

Upvotes: 16

Views: 13034

Answers (2)

ChrisWue
ChrisWue

Reputation: 19070

I guess that either JsonTextWriter or StreamWriter do some internal buffering. So try to flush the jsonWriter and/or the streamWriter before reading from the underlying memory stream.

Upvotes: 2

Jon Skeet
Jon Skeet

Reputation: 1503799

The problem is that you haven't flushed the streamWriter after writing:

serializer.Serialize(jsonWriter, cmd);
streamWriter.Flush();
stream.Position = 0;

Alternatively, why not just use a StringWriter to start with?

using (var writer = new StringWriter())
{
    using (var jsonWriter = new JsonTextWriter(writer))
    {
        serializer.Serialize(jsonWriter, cmd);
        Console.WriteLine(writer.ToString());
    }
}

Upvotes: 21

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