WindowsPhone模拟登陆时如何判断是否已登陆成功？
登陆时访问的页面是http://api.website.com/login.php。若登陆成功，则该页面会返回{"title":1,"userid":1734,"list":[{"s_id":"3"}],"tokenlist":[{"s_id":"3","token":"173899|6.80b926c2778fc1aea416c90e800b8623.2592000.1348992000-261351411","token_secret":"173899|0.ny8z8q4KgpkzST3J5xw4kA5kRr2R230l.261351411","u_id":"261351411"}],"silencetime":{"start_time":"09:00","end_time":"22:00"},"version":10}
若登录失败，则页面返回{"title":2}
登陆代码如下：

private void LoginButton_Click(object sender, RoutedEventArgs e)
{
    try
    {
        API loginapi = new API();
        bool res;
        string username = this.LoginName.Text;
        string password = this.LoginPassword.Text;
        res = loginapi.login(username,password);
        if (res) this.NavigationService.Navigate(new Uri("/MainContentPage.xaml", UriKind.Relative));
    }
    catch (Exception ee)
    {
        MessageBox.Show(ee.ToString());
    }
}

若希望登陆成功才转到MainContentPage.xaml，否则提示“登录失败，密码错误”，该如何实现？
[最优解释]
可以用一个while循环，里面判断连接状态。

int delay = 5;
while (request.statusCode!= HttpStatusCode.OK)
{
    Thread.Sleep(1000);
    delay--;
    if (delay <= 0)
    {
        MessageBox.Show("超时!");
        return false;
    }
}

[其他解释]
我猜这应该是以OAuth作为认证方式的OpenAPI吧。
建议你好好看看OAuth的认证流程，需要几个步骤的。
[其他解释]
用的不是OAuth，是HttpWebRequest等自带类，代码如下：

public string paramData = string.Empty;//请求参数
public string resData = string.Empty;//返回值
public HttpStatusCode statusCode;//状态记录
public Exception errorAsync;//记录异步函数中的错误
public static Encoding dataEncode = Encoding.UTF8;//字符编码方式为UTF8
public void RequestURL(string url)
{
    statusCode = HttpStatusCode.Created;
    HttpWebRequest webReq = (HttpWebRequest)WebRequest.Create(new Uri(url));
    webReq.Method = "POST";
    webReq.ContentType = "application/x-www-form-urlencoded";
    webReq.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), webReq);
}
private void GetRequestStreamCallback(IAsyncResult asynchronousResult)
{
    try
    {
        HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
        Stream postStream = request.EndGetRequestStream(asynchronousResult);
        byte[] byteArray = dataEncode.GetBytes(paramData); 
 
        postStream.Write(byteArray, 0, byteArray.Length);
        postStream.Close();
        request.BeginGetResponse(new AsyncCallback(GetResponseCallback), request);
    }
    catch (Exception ee)
    {
        errorAsync = ee;
    }
}
private void GetResponseCallback(IAsyncResult asynchronousResult)
{
    try
    {
        HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
        HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
        Stream streamResponse = response.GetResponseStream();
        StreamReader streamRead = new StreamReader(streamResponse);
        statusCode = response.StatusCode;
        resData = streamRead.ReadToEnd();
        streamResponse.Close();
        streamRead.Close();
    }
    catch (Exception ee)
    {
        errorAsync = ee;
    }
}

我想通过MessageBox.Show(resData)来查看返回值，可是弹出框里什么也没有，不知道是根本就没有返回值还是我获取返回值的方式不对。