Format Class object into JSON or XML

protected void FormatOutgoingMessage<T>(T graph, string format)
{
    if (format == null)
    {
        format = "json";
    }
    bool flag = format.ToUpper() == "XML";
    WebHeaderCollection headers = WebOperationContext.Current.IncomingRequest.Headers;
    string s = string.Empty;
    string str2 = headers.Get("Accept");
    if (str2 != null)
    {
        bool flag2 = str2.ToLower().Contains("application/json");
        if ((format.ToUpper() == "JSON") || (flag2 && !flag))
        {
            s = Utility.ToJson<T>(graph);
            HttpContext.Current.Response.ContentType = "application/json; charset=utf-8";
            HttpContext.Current.Response.Write(s);
        }
        else
        {
            s = Utility.SerializeDataContract<T>(graph);
            HttpContext.Current.Response.ContentType = "application/xml";
            HttpContext.Current.Response.Write(s);
        }
    }
    else
    {
        s = Utility.SerializeDataContract<T>(graph);
        HttpContext.Current.Response.ContentType = "application/xml";
        HttpContext.Current.Response.Write(s);
    }
}
public static string ToJson<T>(T obj)
{
    DataContractJsonSerializer serializer = new DataContractJsonSerializer(obj.GetType());
    MemoryStream stream = new MemoryStream();
    serializer.WriteObject(stream, obj);
    return Encoding.Default.GetString(stream.ToArray());
}
public static string SerializeDataContract<T>(T graph)
{
    return Serialize<T>(graph, Encoding.UTF8);
}