C# 如何异步检索多个网站？

使用silverlight Windows Phone 8.1项目

我正在尝试从网站加载数据。不过，我必须首先在该站点进行身份验证。 因此，我在网站上发布了一篇文章，使用了来自的CookieAwareWebClient的稍加修改的版本

现在，我让一个WebClient发送一个带有

用户名
和
密码
的
POST
，继续获取我的站点
异步
，并在我的
下载StringCompleted EventHandler
中处理站点数据。
到现在为止，一直都还不错。
现在我想在这一点上扩展，并获得多个网站。
我没有一次就把它们全部拿到手，事实上最好是一个接一个地把它们拿到手

但我不知道该怎么做

到目前为止我的代码：

using System;
using System.Net;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using Windows.Web.Http;
using Microsoft.Phone.Shell;
using StackOverflowApp.Resources;

namespace StackOverflowApp
{
    public partial class MainPage
    {
        private const string URL_DATES = @"/subsite/dates";
        private const string URL_RESULTS = @"/subsite/results";

        private readonly ApplicationBarIconButton btn;

        private int runningOps = 0;
        //Regex's to parse websites
        private readonly Regex regexDates = new Regex(AppResources.regexDates);
        private readonly Regex regexResults = new Regex(AppResources.regexResults);

        private readonly CookieAwareWebClient client = new CookieAwareWebClient();
        private int status;

        // Konstruktor
        public MainPage()
        {
            InitializeComponent();

            btn = ((ApplicationBarIconButton)ApplicationBar.Buttons[0]);

            // = application/x-www-form-urlencoded
            client.Headers[HttpRequestHeader.ContentType] = AppResources.ContentType;
            client.UploadStringCompleted += UploadStringCompleted;
            client.DownloadStringCompleted += DownloadStringCompleted;
        }

        private void GetSite()
        {
            const string POST_STRING = "name={0}&password={1}";

            var settings = new AppSettings();

            if (settings.UsernameSetting.Length < 3 || settings.PasswordSetting.Length < 3)
            {   
                MessageBox.Show(
                    (settings.UsernameSetting.Length < 3 
                        ? "Bitte geben Sie in den Einstellungen einen Benutzernamen ein\r\n" : string.Empty) 
                    +
                    (settings.PasswordSetting.Length < 3
                        ? "Bitte geben Sie in den Einstellungen ein Kennwort ein\r\n" : string.Empty)
                );
                return;
            }


            LoadingBar.IsEnabled = true;     
            LoadingBar.Visibility = Visibility.Visible;
            client.UploadStringAsync(
                new Uri(AppResources.BaseAddress + "subsite/login"),
                "POST",
                string.Format(POST_STRING, settings.UsernameSetting, settings.PasswordSetting));
        }

        private void LoadDates()
        {
            status = 0; //Termine   
            runningOps++;

            client.DownloadStringAsync(new Uri(AppResources.BaseAddress + URL_DATES));
        }

        private void LoadResults()
        {
            status = 1; //Ergebnisse      
            runningOps++;
            client.DownloadStringAsync(new Uri(AppResources.BaseAddress + URL_RESULTS));
        }

        private void DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        {
            runningOps--;
            if (runningOps == 0)
            {
                //alle Operationen sind fertig 
                LoadingBar.IsEnabled = false;
                LoadingBar.Visibility = Visibility.Collapsed;
                btn.IsEnabled = true;
            }
            if (e.Cancelled || e.Error != null) return;

            //Antwort erhalten
            var source = e.Result.Replace("\r", "").Replace("\n", "");
            switch (status)
            {
                case 0: //Termine geladen

                    foreach (Match match in regexDates.Matches(source))
                    {
                        var tb = new TextBlock();
                        var g = match.Groups;

                        tb.Text = string.Format(
                            "{1} {2} {3}{0}{4} {5}{0}{6}",
                            Environment.NewLine,
                            g[1].Value,
                            g[2].Captures.Count > 0 ? g[2].Value : string.Empty,
                            g[3].Captures.Count > 0 ? "- " + g[3].Value : string.Empty,
                            g[5].Value,
                            g[6].Captures.Count > 0 ? "bei " + g[6].Value : string.Empty,
                            (
                                g[7].Captures.Count > 0
                                    ? g[7].Value 
                                    : string.Empty 
                            )
                                + 
                            (
                                g[8].Captures.Count > 0
                                    ? g[8].Value != g[4].Value
                                        ? g[8].Value + " != " + g[4].Value
                                        : g[8].Value
                                    : g[4].Captures.Count > 0
                                        ? g[4].Value
                                        : string.Empty
                            )
                            );

                        DatesPanel.Children.Add(tb);
                    }

                    break;

                case 1: //Ergebnisse geladen
                    foreach (Match match in regexResults.Matches(source))
                    {
                        var tb = new TextBlock();
                        var g = match.Groups;

                        tb.Text = string.Format(
                            "{1} {2} {3}{0}{4} {5}{0}{6}",
                            Environment.NewLine,
                            g[1].Value,
                            g[2].Captures.Count > 0 ? g[2].Value : string.Empty,
                            g[3].Captures.Count > 0 ? "- " + g[3].Value : string.Empty,
                            g[5].Value,
                            g[6].Captures.Count > 0 ? "bei " + g[6].Value : string.Empty,
                            (
                                g[7].Captures.Count > 0
                                    ? g[7].Value 
                                    : string.Empty 
                            )
                                + 
                            (
                                g[8].Captures.Count > 0
                                    ? g[8].Value != g[4].Value
                                        ? g[8].Value + " != " + g[4].Value
                                        : g[8].Value
                                    : g[4].Captures.Count > 0
                                        ? g[4].Value
                                        : string.Empty
                            )
                            );

                        ResultsPanel.Children.Add(tb);
                    }

                    break;
                default:
                    return;
            }
        }

        void UploadStringCompleted(object sender, UploadStringCompletedEventArgs e)
        {
            //Login completed
            LoadDates();
            //THIS WOULD YIELD AN ERROR FROM THE WEBCLIENT SAYING IT ISNT SUPPORTING MULTIPLE ASYNC ACTIONS
            //LoadResults();
        }

        private async void ClickOnRefresh(object sender, EventArgs e)
        {
            var isUp = await IsUp();
            if (isUp)
                GetSite();
            else                                                         
                MessageBox.Show("Die Seite ist down! :(");

        }

        private void ClickOnSettings(object sender, EventArgs e)
        {
            NavigationService.Navigate(new Uri("/Settings.xaml", UriKind.Relative));
        }

        private async Task<bool> IsUp()
        {
            btn.IsEnabled = false;
            const string ISUPMELINK = "http://www.isup.me/{0}";
            var data = await RequestData(string.Format(ISUPMELINK, AppResources.BaseAddress.Replace("https://", string.Empty)));
            var isUp = !data.Contains("It's not just you!");
            btn.IsEnabled = true;

            return isUp;
        }

        private async void ClickOnTestConnection(object sender, EventArgs e)
        {
            var isUp = await IsUp();
            MessageBox.Show(string.Format("Die Seite ist {0}! :{1}", isUp ? "up" : "down", isUp ? ")" : "("));
        }

        private static async Task<string> RequestData(string url)
        {
            using (var httpClient = new HttpClient())
                return await httpClient.GetStringAsync(new Uri(url));
        }
    }
}

使用系统；
Net系统；
使用System.Text.RegularExpressions；
使用System.Threading.Tasks；
使用System.Windows；
使用System.Windows.Controls；
使用Windows.Web.Http；
使用Microsoft.Phone.Shell；
使用StackOverflowApp.Resources；
命名空间StackOverflowApp
{
公共部分类主页
{
私有常量字符串URL_DATES=@“/子网站/日期”；
私有常量字符串URL_RESULTS=@“/子网站/结果”；
专用只读应用程序BariconButton btn；
私有int runningOps=0；
//正则表达式解析网站
private readonly Regex regexDates=新的Regex（AppResources.regexDates）；
private readonly Regex regexResults=new Regex（AppResources.regexResults）；
私有只读CookieAwareWebClient=新CookieAwareWebClient（）；
私人身份；
//康斯特鲁克托
公共主页（）
{
初始化组件（）；
btn=（（ApplicationBarIconButton）ApplicationBar.Buttons[0]）；
//=应用程序/x-www-form-urlencoded
client.Headers[HttpRequestHeader.ContentType]=AppResources.ContentType；
client.UploadStringCompleted+=UploadStringCompleted；
client.DownloadStringCompleted+=DownloadStringCompleted；
}
私有void GetSite（）
{
conststring POST_string=“name={0}&password={1}”；
var settings=新的AppSettings（）；
if（settings.usernameseting.Length<3 | | settings.PasswordSetting.Length<3）
{   
MessageBox.Show(
（settings.usernameseting.Length<3
？“您在安装过程中被咬了一口\r\n”：string.Empty）
+
（settings.PasswordSetting.Length<3
？“您在肯尼沃特的花园里吃了一顿饭\r\n”：string.Empty）
);
返回；
}
LoadingBar.IsEnabled=true；
LoadingBar.Visibility=可见性.Visibility；
client.UploadStringAsync(
新Uri（AppResources.BaseAddress+“子网站/登录”），
“职位”，
Format（POST_string，settings.usernameseting，settings.PasswordSetting））；
}
私有void LoadDates（）
{
状态=0；//终止
runningOps++；
client.DownloadStringAsync（新Uri（AppResources.BaseAddress+URL_DATES））；
}
私有void LoadResults（）
{
status=1；//Ergebnisse
runningOps++；
DownloadStringAsync（新Uri（AppResources.BaseAddress+URL_结果））；
}
私有void DownloadStringCompleted已完成（对象发送方，DownloadStringCompletedEventArgs e）
{
运行操作--；
如果（运行操作==0）
{
//所有的操作都在进行中
LoadingBar.IsEnabled=false；
LoadingBar.Visibility=Visibility.collazed；
btn.IsEnabled=true；
}
如果（e.取消| | e.错误！=null）返回；
//益母草
var source=e.Result.Replace（“\r”，”）.Replace（“\n”，”）；
开关（状态）
{
案例0://Termine geladen
foreach（regexDates.Matches中的匹配（源））
{
var tb=新的TextBlock（）；
var g=匹配组；
tb.Text=string.Format(
"{1} {2} {3}{0}{4} {5}{0}{6}",
环境，新线，
g[1].值，
g[2]。Captures.Count>0？g[2]。值：string.Empty，
g[3]。Captures.Count>0？”-“+g[3]。值：string.Empty，
g[5].值，
g[6]。Captures.Count>0？“bei”+g[6]。值：string.Empty，
(
g[7].Captures.Count>0
？g[7]。数值
：string.Empty
)
+ 
(
g[8].Captures.Count>0
？g[8]。值！=g[4]。值
？g[8]。值+“！=”+g[4]。值
：g[8]。值
：g[4].捕获数.Count>0
？g[4]。数值
：string.Empty
)
);
DatesPanel.Children.Add（tb）；
}
打破
案例1://Ergebnisse geladen
foreach（regexResults.Matches中的匹配（源））
{
var tb=新的TextBlock（）；
var g=m
using System;
using System.Net;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using Windows.Web.Http;
using Microsoft.Phone.Shell;
using StackOverflowApp.Resources;

namespace StackOverflowApp
{
    public partial class MainPage
    {
        private const string URL_DATES = @"/subsite/dates";
        private const string URL_RESULTS = @"/subsite/results";

        private readonly ApplicationBarIconButton btn;

        private int runningOps = 0;
        //Regex's to parse websites
        private readonly Regex regexDates = new Regex(AppResources.regexDates);
        private readonly Regex regexResults = new Regex(AppResources.regexResults);

        private readonly CookieAwareWebClient client = new CookieAwareWebClient();
        private int status;

        // Konstruktor
        public MainPage()
        {
            InitializeComponent();

            btn = ((ApplicationBarIconButton)ApplicationBar.Buttons[0]);

            // = application/x-www-form-urlencoded
            client.Headers[HttpRequestHeader.ContentType] = AppResources.ContentType;
            client.UploadStringCompleted += UploadStringCompleted;
            client.DownloadStringCompleted += DownloadStringCompleted;
        }

        private void GetSite()
        {
            const string POST_STRING = "name={0}&password={1}";

            var settings = new AppSettings();

            if (settings.UsernameSetting.Length < 3 || settings.PasswordSetting.Length < 3)
            {   
                MessageBox.Show(
                    (settings.UsernameSetting.Length < 3 
                        ? "Bitte geben Sie in den Einstellungen einen Benutzernamen ein\r\n" : string.Empty) 
                    +
                    (settings.PasswordSetting.Length < 3
                        ? "Bitte geben Sie in den Einstellungen ein Kennwort ein\r\n" : string.Empty)
                );
                return;
            }


            LoadingBar.IsEnabled = true;     
            LoadingBar.Visibility = Visibility.Visible;
            client.UploadStringAsync(
                new Uri(AppResources.BaseAddress + "subsite/login"),
                "POST",
                string.Format(POST_STRING, settings.UsernameSetting, settings.PasswordSetting));
        }

        private void LoadDates()
        {
            status = 0; //Termine   
            runningOps++;

            client.DownloadStringAsync(new Uri(AppResources.BaseAddress + URL_DATES));
        }

        private void LoadResults()
        {
            status = 1; //Ergebnisse      
            runningOps++;
            client.DownloadStringAsync(new Uri(AppResources.BaseAddress + URL_RESULTS));
        }

        private void DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        {
            runningOps--;
            if (runningOps == 0)
            {
                //alle Operationen sind fertig 
                LoadingBar.IsEnabled = false;
                LoadingBar.Visibility = Visibility.Collapsed;
                btn.IsEnabled = true;
            }
            if (e.Cancelled || e.Error != null) return;

            //Antwort erhalten
            var source = e.Result.Replace("\r", "").Replace("\n", "");
            switch (status)
            {
                case 0: //Termine geladen

                    foreach (Match match in regexDates.Matches(source))
                    {
                        var tb = new TextBlock();
                        var g = match.Groups;

                        tb.Text = string.Format(
                            "{1} {2} {3}{0}{4} {5}{0}{6}",
                            Environment.NewLine,
                            g[1].Value,
                            g[2].Captures.Count > 0 ? g[2].Value : string.Empty,
                            g[3].Captures.Count > 0 ? "- " + g[3].Value : string.Empty,
                            g[5].Value,
                            g[6].Captures.Count > 0 ? "bei " + g[6].Value : string.Empty,
                            (
                                g[7].Captures.Count > 0
                                    ? g[7].Value 
                                    : string.Empty 
                            )
                                + 
                            (
                                g[8].Captures.Count > 0
                                    ? g[8].Value != g[4].Value
                                        ? g[8].Value + " != " + g[4].Value
                                        : g[8].Value
                                    : g[4].Captures.Count > 0
                                        ? g[4].Value
                                        : string.Empty
                            )
                            );

                        DatesPanel.Children.Add(tb);
                    }

                    break;

                case 1: //Ergebnisse geladen
                    foreach (Match match in regexResults.Matches(source))
                    {
                        var tb = new TextBlock();
                        var g = match.Groups;

                        tb.Text = string.Format(
                            "{1} {2} {3}{0}{4} {5}{0}{6}",
                            Environment.NewLine,
                            g[1].Value,
                            g[2].Captures.Count > 0 ? g[2].Value : string.Empty,
                            g[3].Captures.Count > 0 ? "- " + g[3].Value : string.Empty,
                            g[5].Value,
                            g[6].Captures.Count > 0 ? "bei " + g[6].Value : string.Empty,
                            (
                                g[7].Captures.Count > 0
                                    ? g[7].Value 
                                    : string.Empty 
                            )
                                + 
                            (
                                g[8].Captures.Count > 0
                                    ? g[8].Value != g[4].Value
                                        ? g[8].Value + " != " + g[4].Value
                                        : g[8].Value
                                    : g[4].Captures.Count > 0
                                        ? g[4].Value
                                        : string.Empty
                            )
                            );

                        ResultsPanel.Children.Add(tb);
                    }

                    break;
                default:
                    return;
            }
        }

        void UploadStringCompleted(object sender, UploadStringCompletedEventArgs e)
        {
            //Login completed
            LoadDates();
            //THIS WOULD YIELD AN ERROR FROM THE WEBCLIENT SAYING IT ISNT SUPPORTING MULTIPLE ASYNC ACTIONS
            //LoadResults();
        }

        private async void ClickOnRefresh(object sender, EventArgs e)
        {
            var isUp = await IsUp();
            if (isUp)
                GetSite();
            else                                                         
                MessageBox.Show("Die Seite ist down! :(");

        }

        private void ClickOnSettings(object sender, EventArgs e)
        {
            NavigationService.Navigate(new Uri("/Settings.xaml", UriKind.Relative));
        }

        private async Task<bool> IsUp()
        {
            btn.IsEnabled = false;
            const string ISUPMELINK = "http://www.isup.me/{0}";
            var data = await RequestData(string.Format(ISUPMELINK, AppResources.BaseAddress.Replace("https://", string.Empty)));
            var isUp = !data.Contains("It's not just you!");
            btn.IsEnabled = true;

            return isUp;
        }

        private async void ClickOnTestConnection(object sender, EventArgs e)
        {
            var isUp = await IsUp();
            MessageBox.Show(string.Format("Die Seite ist {0}! :{1}", isUp ? "up" : "down", isUp ? ")" : "("));
        }

        private static async Task<string> RequestData(string url)
        {
            using (var httpClient = new HttpClient())
                return await httpClient.GetStringAsync(new Uri(url));
        }
    }
}