Return value of UploadStringAsync().?

Question

My question is correct or incorrect I don't know, but I would like to know if is it possible to return the value of UploadStringAsync() of post methods using WebClient?

    string serviceURL = REST_URI + servicePath;
    Uri URI = new Uri(serviceURL);
    System.Net.WebClient webClient = new WebClient();
    webClient.Headers["ContentType"] = "application/json";
    webClient.Headers["Accept"] = "application/json";
    webClient.UploadStringCompleted += this.sendPostCompleted;
    webClient.UploadStringAsync(URI, HTTP_POST, result);
    return ??;

If we can return the value of UploadStringAsync(URI, HTTP_POST, result); please let me know?

Answer 1

You can use UploadStringCompleted event and get result in event handler. Once upload completes (failed or succeed) event is raised.

Attach

client.UploadStringCompleted 
               += new UploadStringCompletedEventHandler (UploadStringCallback2);

Use:

void UploadStringCallback2(object sender, UploadStringCompletedEventArgs e)
{
//e.Result use it
}

If you want to return result of the upload you can wait for event to be raised like here using AutoResetEvent

Answer 2

From .NET 4.5 we can use UploadStringTaskAsync to retrieve return value directly.

string rspBody = await client.UploadStringTaskAsync(uri, "POST");

ref: MSDN