从ASP发送推送通知.. NET到Android应用程序

我想从我的ASP发送一个小的推送通知。Post方法到我的简单Android应用程序。以下是我所有的尝试和重新搜索。

我正在使用谷歌云消息服务发送通知到应用程序。我的应用程序接收它的名称值对。我还在这里给出了服务器代码的Java版本和我的Post方法中的c#实现。但是我的方法抛出一个异常Android应用程序中的"Exception occurred with Error as(15913): println needs a message"

服务器部分的工作Java代码如下:-

public void sendmessage2Device(View v,String regisID,String msg1,String msg2) {
    HttpClient client = new DefaultHttpClient();
    HttpPost post = new HttpPost(
            "https://android.googleapis.com/gcm/send");

    try {
        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
        nameValuePairs.add(new BasicNameValuePair("registration_id",regisID));
        nameValuePairs.add(new BasicNameValuePair("data1",msg1));
        nameValuePairs.add(new BasicNameValuePair("data2", msg2));



        post.setHeader("Authorization","key=AIzaSyBB6igK9sYYBTSIly6SRUHFVexeOa_7FuM");
        post.setHeader("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");


        post.setEntity(new UrlEncodedFormEntity(nameValuePairs));
        HttpResponse response = client.execute(post);
        InputStreamReader inputst = new InputStreamReader(response.getEntity().getContent());
        BufferedReader rd = new BufferedReader(inputst);

        String line = "";
        while ((line = rd.readLine()) != null) {
            Log.e("HttpResponse", line);

                String s = line.substring(0);
                Log.i("GCM response",s);
                //Toast.makeText(v.getContext(), s, Toast.LENGTH_LONG).show();

        }
    } catch (IOException e) {
        e.printStackTrace();
    }

同样，我的c#代码在ASP。. NET WEB API如下:

public String Post([FromBody]TransactionDetails value)
    {
        try
        {
            WebClient toGCM = new WebClient();
            toGCM.Headers.Add("ContentType:");
            toGCM.Headers["ContentType"] = "application/x-www-form-urlencoded; charset=UTF-8";
            //HttpWebRequest toGCM = (HttpWebRequest)WebRequest.Create("https://android.googleapis.com/gcm/send");
            //toGCM.ContentType = "application/x-www-form-urlencoded; charset=UTF-8";
            toGCM.Headers.Add("Accept:");
            toGCM.Headers["Accept"]= "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.114 Safari/537.36";
            //toGCM.Accept = "application/json, text/javascript, */*; q=0.01";
            toGCM.Headers.Add("UserAgent:") ;
            toGCM.Headers["UserAgent"]= "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.114 Safari/537.36";
            toGCM.Headers.Add("Authorization:");
            toGCM.Headers["Authorization"] = "key=AIzaSyCoxjeOGi_1ss2TeShDcoYbNcPU9_0J_TY";
            //String DatatoClient = "ToAccountNumber=" + value.ToAccountNumber + "&Amount=" + value.Amount;
            NameValueCollection postFieldNameValue = new NameValueCollection();
            postFieldNameValue.Add("registration_id", "APA91bHzO52-3TsEIMV3RXi45ICIo9HOe1ospPl3gRYwAAw59ATHvadGPZN86heHOQJNU8syju-yD9UQqSgkZOqllGi5AoSPMRRuw3RYhgApflr0abLoAh2GWFQCZgToG_aM0rOg0lBV8osz6ZMtP1JBF1S9_DiWiqKRT5WL6qFz4PqyE0jCHsE");
            postFieldNameValue.Add("Account", value.ToAccountNumber.ToString());
            postFieldNameValue.Add("Amount", value.Amount.ToString());
            byte[] responseArray = toGCM.UploadValues("https://android.googleapis.com/gcm/send", postFieldNameValue);
            String S=Encoding.ASCII.GetString(responseArray);
            return S;
        }
        catch (Exception e)
        {
            Console.WriteLine("Exception Occured in Post Method on Web Server as:{0}", e.Message);
            return e.Message;
        }
    }

在Android APP中，我有以下LOC for Receiver…

public void onReceive(Context context, Intent intent) {
    try {
        String action = intent.getAction();
        if (action.equals("com.google.android.c2dm.intent.REGISTRATION"))
        {
            String registrationId = intent.getStringExtra("registration_id");
            Log.i("Received the Registration Id as ",registrationId);
            String error = intent.getStringExtra("error");
            String unregistered = intent.getStringExtra("unregistered"); 
        }
        else if (action.equals("com.google.android.c2dm.intent.RECEIVE")) 
        {
            Log.i("In the RECEIVE Method ",intent.getStringExtra("Account"));
            String Account = intent.getStringExtra("Account");
            String Amount = intent.getStringExtra("Amount");
            Log.i("Received Account as ",Account);
            Log.i("Received Amount as  ",Amount);
        }
    }
    catch(Exception e)
    {
        Log.i("Exception Occured with Error as ",e.getMessage());
    }
    finally
    {
    }

我对Android开发非常陌生，这是我的第一个Helloworld Android应用程序。谁能告诉我我做错了什么，为什么异常被抛出，以及如何纠正它?