如何從HttpWebRequest更新UI？

Question

在我的Mainpage.xaml.cs文件中，我有一個函數可以創建另一個類的實例，並嘗試從該實例使用HttpWebRequest下載網頁。問題是，一旦我設法下載網頁，我無法將其發送回主UI線程。我試過使用Deployment.Current.Dispatcher.BeginInvoke將網頁發送回TextBlock，我有等待，但是當我嘗試時，我收到一個錯誤，告訴我無法從其他類訪問TextBlock。有沒有辦法在兩個線程之間傳遞數據而不使用LocalStorage？

編輯：下面的代碼：

的MainPage：

private void button1_Click(object sender, RoutedEventArgs e) 
    { 
     Member m = new Member(name, id); 
    } 

會員等級：

public Member(String Member, String API) 
    { 
     APIKey = API; 
     MemberName = Member; 
     this.super = super; 
     DoSend(method, string, "", null); 
    } 

public void DoSend(string method, string url, string body, string mimetype) 
    { 
     if (WebRequest.RegisterPrefix("https://",System.Net.Browser.WebRequestCreator.ClientHttp)) { 
      HttpWebRequest request = WebRequest.Create(makeURI(url)) as HttpWebRequest; 

     request.Method = method; 
     request.Headers["X-NFSN-Authentication"] = MakeAuthHeader(url,body); 
     if (body != "") 
     { 
      byte[] bodyData = Encoding.UTF8.GetBytes(body); 
      request.ContentType = mimetype; 
      //Stuff Should Happen Here 
     } 

     else 
      doStuff(request); 
     } 

public void doStuff(HttpWebRequest httpReq) 
    { 
     httpReq.BeginGetResponse(r => 
     { 
      var httpRequest = (HttpWebRequest)r.AsyncState; 
      var httpResponse = (HttpWebResponse)httpRequest.EndGetResponse(r); 

      using (var reader = new StreamReader(httpResponse.GetResponseStream())) 
      { 
       var response = reader.ReadToEnd(); 
       ResponseBlock.Text = response; //Invalid cross-thread reference 
      } 
     }, httpReq); 
    } 

Answer 1

的MainPage：

customClass.DownloadPage((result) => 
{ 
    textBlock.Text = result; 
}, 
(exception) => 
{ 
    MessageBox.Show(exception.Message); 
}); 

CustomClass：

public void DownloadPage(Action<string> callback, Action<Exception> exception) 
{ 
    WebClient webClient = new WebClient(); 
    webClient.DonwloadStringCompleted += (s, e) => 
    { 
     if (e.Error == null) 
     { 
      Deployment.Current.Dispatcher.BeginInvoke(() => 
      { 
       callback(e.Result); 
      }); 
     } 
     else 
     { 
      Deployment.Current.Dispatcher.BeginInvoke(() => 
      { 
       exception(e.Error); 
      }); 
     } 
    }; 
    webClient.DonwloadStringAsync(); 
}