如何解决这个问题“远程服务器返回错误：NotFound”？

Question

我试图解决这个问题，但遗憾的是没有什么对我有帮助。我在下面列出了带有***错误点的代码。我需要帮助，请告诉我代码有什么问题。

代码：

public MainViewModel()
{

    System.Uri myUri = new System.Uri("http://192.168.0.103/new_ringtone");
    HttpWebRequest myRequest = (HttpWebRequest)HttpWebRequest.Create(myUri);
    myRequest.Method = "POST";
    myRequest.ContentType = "application/json;charset=utf-8";
    myRequest.Headers["user-agent"] = "RingtoneApplication";
    myRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), myRequest);          
}

void GetRequestStreamCallback(IAsyncResult callbackResult)
{
    HttpWebRequest myRequest = (HttpWebRequest)callbackResult.AsyncState;
    // End the stream request operation
    Stream postStream = myRequest.EndGetRequestStream(callbackResult);
    // Create the post data
    string currentDateTime = DateTime.Now.ToShortDateString();
    string deviceName = Microsoft.Phone.Info.DeviceStatus.DeviceName;
    string osVersion =Environment.OSVersion.Version.ToString();

    Dictionary<string, object> userInfoDictionary = new Dictionary<string, object>();
    userInfoDictionary.Add("DeviceName", deviceName);
    userInfoDictionary.Add("OSVersion", osVersion);
    userInfoDictionary.Add("DateTime", currentDateTime);
    Dictionary<string, object> user = new Dictionary<string, object>();
    user.Add("User", userInfoDictionary);

    Dictionary<string, string> ringtoneappDictionary = new Dictionary<string, string>();
    ringtoneappDictionary.Add("Ringtoneapp", "category_id");

    Dictionary<string, string> userAgent = new Dictionary<string, string>();
    userAgent.Add("UserAgent", "RingtoneApplication");

    Object[] dataArray = new object[2];
    dataArray[0] = user;
    dataArray[1] = ringtoneappDictionary;
    //dataArray[2] = userAgent;

    Dictionary<string, Array> data = new Dictionary<string, Array>();
    data.Add("Data", dataArray);

    string jsonData = JsonConvert.SerializeObject(data);

    var token = CreateToken(jsonData, GlobalClass.SecretKey);



    string postData = "method=getRintoneCategories&data="+jsonData+"&Token="+token;
    byte[] byteArray = Encoding.UTF8.GetBytes(postData);
    // Add the post data to the web request
    postStream.Write(byteArray, 0, byteArray.Length);
    postStream.Close();
    // Start the web request
    myRequest.BeginGetResponse(new AsyncCallback(GetResponsetStreamCallback), myRequest);
}

void GetResponsetStreamCallback(IAsyncResult callbackResult)
{
    HttpWebRequest request = (HttpWebRequest)callbackResult.AsyncState;
    ***HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(callbackResult);***
    using (StreamReader httpWebStreamReader = new StreamReader(response.GetResponseStream()))
    {
        string result = httpWebStreamReader.ReadToEnd();
        //For debug: show results
        Debug.WriteLine(result);
    }
}

例外：

{System.Net.WebException: The remote server returned an error: NotFound. ---> System.Net.WebException: The remote server returned an error: NotFound.
at System.Net.Browser.ClientHttpWebRequest.InternalEndGetResponse(IAsyncResult asyncResult)
at System.Net.Browser.ClientHttpWebRequest.<>c__DisplayClasse.<EndGetResponse>b__d(Object sendState)
at System.Net.Browser.AsyncHelper.<>c__DisplayClass1.<BeginOnUI>b__0(Object sendState)
   --- End of inner exception stack trace ---
at System.Net.Browser.AsyncHelper.BeginOnUI(SendOrPostCallback beginMethod, Object state)
at System.Net.Browser.ClientHttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
at Ringtone.ViewModel.MainViewModel.GetResponsetStreamCallback(IAsyncResult callbackResult)
at System.Net.Browser.ClientHttpWebRequest.<>c__DisplayClass1d.<InvokeGetResponseCallback>b__1b(Object state2)}