从System.Net.WebClient的响应获取请求的URL？

Question

我正在使用System.Net.WebClient从URL中检索一些数据.

void GetAirportData()
{
  var url = "http://server.example.com/airports.xml?id=OSL";
  var webClient = new WebClient();
  webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);
  webClient.OpenReadAsync(new Uri(url, UriKind.Absolute));
}

void webClient_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
   //How can I see the original URL here, so that I can see which id parameter was passed?
}

我发送的请求将包含一个URL,其中包含一些参数,这些参数会针对每个调用进行更改,我需要知道响应响应时我要求的参数.

我可以使用例如sender对象的.UserState属性吗？

Answer 1

好吧,如果需要URL,我会将您的代码更改为以下内容:

void GetAirportData()
{
  var url = new Uri("http://server.example.com/airports.xml?id=OSL", UriKind.Absolute);
  var webClient = new WebClient();
  webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);
  webClient.OpenReadAsync(url, url);
}

void webClient_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
   // Gets the original url passed.
   var url = e.UserState as Uri;
}