Windows 手机 - httpwebrequest - 将 ref 变量传递给回调

Question

我正在从 Windows Phone 应用程序发送 HttpWebRequest：

HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(new Uri("myurl"));
request.BeginGetResponse(MyProcessor, request);

这里是回调：

public void MyProcessor(IAsyncResult asynchronousResult)
{
     HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
     HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
     using (StreamReader streamReader = new StreamReader(response.GetResponseStream()))
     {
          string text = streamReader.ReadToEnd();
          // passing some arguments to special class, that generates ui elements
      }
}

这里是生成器类的方法

public static void AddEventTypeToList(some parameters)
{
       Deployment.Current.Dispatcher.BeginInvoke(() =>
       {
             //xaml generating
       });
}            

所以。我需要使用 Dispatcher.BeginInvoke，否则我会得到“无效的跨线程访问”。

但是。我还需要传递对某些参数的引用...并且我收到错误“您不能在匿名方法、lambda 表达式或查询表达式中使用关键字 ref 或 out 用户参数。

怎么办？我通常需要使用 HttpWebRequest（因为我需要使用状态码并且它会阻止我的 WebClient）并将对某些 ui 元素的引用传递给回调中的特殊 uigenerator 类

---

我尝试了 Mangist 的答案，但我认为有一些错误：

public static void AddEventTypeToList(EventType ev, ListBox mainListBox, ref List<Grid> inds)
{
      Deployment.Current.Dispatcher.BeginInvoke(new Action<EventType, ListBox, List<Grid>>(DoOnUIThread));

}

生成：

 public static void DoOnUIThread(EventType ev, ListBox mainListBox, List<Grid> inds)
 {
       Grid gr = new Grid();
       //....
 }

这个方法根本没有到达断点

Answer 1

我会使用async/await。生活可以更轻松...

HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(new Uri("myurl"));
var response = await request.GetResponseAsync();

using (StreamReader streamReader = new StreamReader(response.GetResponseStream()))
{
    string text = streamReader.ReadToEnd();
    // Updating UI is safe. Do it whichever way you want!!!
}

编辑

你也可以使用HttpClient

using (HttpClient client = new HttpClient())
{
    string text = await client.GetStringAsync("myurl");    
    //update UI here
}

Answer 2

public static void DoOnUIThread(some parameters)
{
  // You can use parameters now.  Obviously "some" is not a type, but you would replace this with the type you're using for your parameters.
}

public static void AddEventTypeToList(some parameters)
{
    // Change Action<Type> to use the type of the parameter you want
       Deployment.Current.Dispatcher.BeginInvoke(new Action<some>(DoOnUIThread));
}