how to parse xml string from Post method response? - data-binding

Question

I have a xml string that return from Post method:
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();
}
The responseString is the string I want to parse, using parseXmlString class below. However I can't call the method parseXmlString directly because of the static. How can I pass the responseString to the parseXmlString method to have them parse out and bind to the listBox. Or anyway to have the same result would be great.
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

Your approach is inversed logic. You know that you can have return values on methods, right?-)
What you need to do is let your ParseXmlString method take the responseString as a parameter, and let it return the created IEnumerable, like this:
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"),
};
}
And change your async code handling, to perform a callback to your UI thread, when it's done reading out the responseString.
Then, on your UI thread, you would do:
// This being your method to get the async response
GetResponseAsync(..., responseString =>
{
var searchResults = ParseXmlString(responseString);
listBox2.ItemsSource = searchResults;
})
You can see this answer, if you need some basic understanding of callbacks: Callbacks in C#