如何从 Post 方法响应中解析 xml 字符串？

Question

我有一个从 Post 方法返回的 xml 字符串：

private static void GetResponseCallback(IAsyncResult asynchronousResult)
{
    HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;

    // End the operation
    HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
    HttpStatusCode rcode = response.StatusCode;

    var stream = new GZipInputStream(response.GetResponseStream());
    using (StreamReader reader = new StreamReader(stream))
    {
        responseString = reader.ReadToEnd();                
    }          

    response.Close();
}

responseString 是我要解析的字符串，使用下面的 parseXmlString 类。但是由于静态，我不能直接调用方法 parseXmlString。如何将 responseString 传递给 parseXmlString 方法以让它们解析出来并绑定到 listBox。或者无论如何，获得相同的结果会很棒。

void parseXmlString()
{
    byte[] byteArray = Encoding.UTF8.GetBytes(responseString);
    MemoryStream str = new MemoryStream(byteArray);
    str.Position = 0;

    XDocument xdoc = XDocument.Load(str);

    var data = from query in xdoc.Descendants("tracks").Elements("item")
               select new searchResult
               {
                   artist = (string)query.Element("artist"),
                   album = (string)query.Element("album"),
                   track = (string)query.Element("track"),
                   //   artistA = (string)query.Element("artists").Element("artist"),
               };
    //  ListBox lb = new ListBox();

    listBox1.ItemsSource = data;

    var data1 = from query in xdoc.Descendants("artists").Elements("item")
                select new searchResult
                {
                    artistA = (string)query.Element("artist"),
                };
    listBox2.ItemsSource = data1;
}

Answer 1

你的方法是逆逻辑。你知道你可以在方法上有返回值，对吧？-)

您需要做的是让您的ParseXmlString 方法将responseString 作为参数，并让它返回创建的IEnumerable，如下所示：

private IEnumerable<SearchResult> ParseXmlString(responseString)
{
    XDocument xdoc = XDocument.Load(responseString);

    var data =
        from query in xdoc.Descendants("tracks").Elements("item")
        select new SearchResult
        {
           Artist = (string)query.Element("artist"),
           Album = (string)query.Element("album"),
           Track = (string)query.Element("track"),
        };

    return
        from query in xdoc.Descendants("artists").Elements("item")
        select new SearchResult
        {
           ArtistA = (string)query.Element("artist"),
        };
}

并更改您的异步代码处理，以在读取 responseString 完成后对您的 UI 线程执行回调。 然后，在你的 UI 线程上，你会这样做：

// This being your method to get the async response
GetResponseAsync(..., responseString =>
{
    var searchResults = ParseXmlString(responseString);
    listBox2.ItemsSource = searchResults;
})

如果你需要对回调有一些基本的了解，可以看这个答案：Callbacks in C#