For the provided example AutoResetEvent class
could be utilized to control the flow, in particular to wait asynchronous WebClient.OpenReadCompleted
Event is completed like this:
class Program
{
private static readonly string ApiKey = System.Configuration.ConfigurationManager.AppSettings.Get("BingMapsKey");
private static readonly AutoResetEvent StopWaitHandle = new AutoResetEvent(false);
public static void Main()
{
var query = "1 Microsoft Way, Redmond, WA";
BingMapsRESTToolkit.Location result = null;
Uri geocodeRequest = new Uri(string.Format("http://dev.virtualearth.net/REST/v1/Locations?q={0}&key={1}",
query, ApiKey));
GetResponse(geocodeRequest, (x) =>
{
if (response != null &&
response.ResourceSets != null &&
response.ResourceSets.Length > 0 &&
response.ResourceSets[0].Resources != null &&
response.ResourceSets[0].Resources.Length > 0)
{
result = response.ResourceSets[0].Resources[0] as BingMapsRESTToolkit.Location;
}
});
StopWaitHandle.WaitOne(); //wait for callback
Console.WriteLine(result.Point); //<-access result
Console.ReadLine();
}
private static void GetResponse(Uri uri, Action<Response> callback)
{
var wc = new WebClient();
wc.OpenReadCompleted += (o, a) =>
{
if (callback != null)
{
DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(Response));
callback(ser.ReadObject(a.Result) as Response);
}
StopWaitHandle.Set(); //signal the wait handle
};
wc.OpenReadAsync(uri);
}
}
Option 2
Or to switch to ServiceManager class
that makes it easy when working via asynchronous programming model:
public static void Main()
{
var task = ExecuteQuery("1 Microsoft Way, Redmond, WA");
task.Wait();
Console.WriteLine(task.Result);
Console.ReadLine();
}
where
public static async Task<BingMapsRESTToolkit.Location> ExecuteQuery(string queryText)
{
//Create a request.
var request = new GeocodeRequest()
{
Query = queryText,
MaxResults = 1,
BingMapsKey = ApiKey
};
//Process the request by using the ServiceManager.
var response = await request.Execute();
if (response != null &&
response.ResourceSets != null &&
response.ResourceSets.Length > 0 &&
response.ResourceSets[0].Resources != null &&
response.ResourceSets[0].Resources.Length > 0)
{
return response.ResourceSets[0].Resources[0] as BingMapsRESTToolkit.Location;
}
return null;
}
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