Using Task.wait() application hangs and never returns

c#, google-api, reverse-geocoding, task, wait

Solution

I don't understand why you use `DownloadStringCompleted` event and try to make it blocking. If you want to wait the result, just use blocking call `DownloadString`

var location = RetrieveFormatedAddress(51.962146, 7.602304);

string RetrieveFormatedAddress(double lat, double lon)
{
    using (WebClient client = new WebClient())
    {
        string xml = client.DownloadString(String.Format(baseUri, lat, lon));
        return ParseXml(xml);
    }
}

private static string ParseXml(string xml)
{
    var result = XDocument.Parse(xml)
                .Descendants("formatted_address")
                .FirstOrDefault();
    if (result != null)
        return result.Value;
    else
        return "No Address Found";
}

If you want to make it async

var location = await RetrieveFormatedAddressAsync(51.962146, 7.602304);

async Task<string> RetrieveFormatedAddressAsync(double lat,double lon)
{
    using(HttpClient client = new HttpClient())
    {
        string xml =  await client.GetStringAsync(String.Format(baseUri,lat,lon));
        return ParseXml(xml);
    }
}

Problem

I am new to C# and using `Task`. I was trying to run this application but my application hangs every time. When I am adding `task.wait()`, it keeps waiting and never returns. Any help is much appreciated. EDIT: I want to call DownloadString Asynchronously. And when I am doing task.Start() as suggested by "Austin Salonen" I don't get the address of location but default value in location string from returnVal. It means that location got value assigned before task got completed. How can I make sure that after task is completed only then location gets assigned returnVal. ``` public class ReverseGeoCoding { static string baseUri = "http://maps.googleapis.com/maps/api/geocode/xml?latlng={0},{1}&sensor=false"; string location = "default"; static string returnVal = "defaultRet"; string latitude = "51.962146"; string longitude = "7.602304"; public string getLocation() { Task task = new Task(() => RetrieveFormatedAddress(latitude, longitude)); //var result = Task.Factory.StartNew(RetrieveFormatedAddress("51.962146", "7.602304")); task.Wait(); //RetrieveFormatedAddress("51.962146", "7.602304"); location = returnVal; return location; } public static void RetrieveFormatedAddress(string lat, string lng) { string requestUri = string.Format(baseUri, lat, lng); using (WebClient wc = new WebClient()) { wc.DownloadStringCompleted += new DownloadStringCompletedEventHandler(wc_DownloadStringCompleted); wc.DownloadStringAsync(new Uri(requestUri)); } } static void wc_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e) { var xmlElm = XElement.Parse(e.Result); var status = (from elm in xmlElm.Descendants() where elm.Name == "status" select elm).FirstOrDefault(); if (status.Value.ToLower() == "ok") { var res = (from elm in xmlElm.Descendants() where elm.Name == "formatted_address" select elm).FirstOrDefault(); //Console.WriteLine(res.Value); returnVal = res.Value; } else { returnVal = "No Address Found"; //Console.WriteLine("No Address Found"); } } } ```

Original source