asp.net - REST WebService C# is not accepting Emoticons -

i have rest webservice accepts feedback windows 8.1 app. works until user inserts emoticon text.

example: awesome!! 😃

when happens get:{statuscode: 400, reasonphrase: 'bad request', version: 1.1, content: system.net.http.streamcontent, headers: { date: thu, 16 jul 2015 21:05:54 gmt server: microsoft-iis/10.0 x-powered-by: asp.net content-length: 1806 content-type: text/html }}

i have no idea why happening.

here code service:

    [operationcontract]     [webinvoke(         method = "post",          responseformat = webmessageformat.json,         requestformat = webmessageformat.json,         uritemplate = "postfeedback")]     void capturefeedback(feedback tmpfeedback); 

the processing code:

    public void capturefeedback(feedback myfeedback)     {         using (dbemployeedirectoryentities entities = new dbemployeedirectoryentities())         {             feedback tmpfeedback = new feedback();              tmpfeedback.feedbackguid = system.guid.newguid().tostring();             tmpfeedback.rating = myfeedback.rating;             tmpfeedback.feedbackmessage = myfeedback.feedbackmessage;             tmpfeedback.timestamp = myfeedback.timestamp;             tmpfeedback.hostname = myfeedback.hostname;              entities.feedbacks.add(myfeedback);              entities.savechanges();         }     } 

the class:

    public partial class feedback     {        public string feedbackguid { get; set; }        public nullable<int> rating { get; set; }        public string feedbackmessage { get; set; }        public nullable<system.datetime> timestamp { get; set; }        public string hostname { get; set; }     } 

i encoding request utf8:

httpresponsemessage myresponse = null;

        var myclient = new httpclient();          myclient.baseaddress = new uri(baseaddress);          var content = new stringcontent(myjson, encoding.utf8, "application/json");          try         {             myresponse = await myclient.postasync(myuri, content);             return myresponse;         }         catch (exception ex)         {             throw ex;         } 

any ideas?

please check out:

https://en.wikipedia.org/wiki/utf-8

https://en.wikipedia.org/wiki/emoji

utf8 not support range emoji characters. you'll need utf32

https://msdn.microsoft.com/en-us/library/system.text.utf32encoding(v=vs.110).aspx