C# WebClient.DownloadString抛出一个'；System.Net.WebException'；

WebClient.DownloadString每次运行时都会失败，在System.dll中引发“System.Net.WebException”。它的名称有什么问题吗？代码如下

using (var wc = new WebClient())
            {
                wc.Headers["Authorization"] = string.Format("Basic {0}", ConfigurationManager.AppSettings["which_api_token"]);
                try
                {
                    var jsonString = wc.DownloadString(string.Format("{0}/subjects/{1}", 
                            ConfigurationManager.AppSettings["which_api_url"], 
                            Uri.EscapeDataString(subjectName)));
                    return result;
                }
                catch(Exception ex)
                {
                    result.Status = ResultStatus.Failed;
                    return result;
                }
           }

---

WebException为您提供了错误信息

using (var wc = new WebClient())
{
    wc.Headers["Authorization"] = string.Format("Basic {0}", ConfigurationManager.AppSettings["which_api_token"]);
    try
    {
        var jsonString = wc.DownloadString(string.Format("{0}/subjects/{1}", 
                ConfigurationManager.AppSettings["which_api_url"], 
                Uri.EscapeDataString(subjectName)));
        return result;
    }
    catch(Exception ex)
    {
        WebException we = ex as WebException;
        if (we != null && we.Response is HttpWebResponse)
        {
            HttpWebResponse response = (HttpWebResponse)we.Response;
            // it can be 404, 500 etc...
            Console.WriteLine(response.StatusCode);
        }
        result.Status = ResultStatus.Failed;
        return result;
    }
}

---

异常的消息是什么？也许可以解释一下，你没有做任何关于

异常的事情

你正在“捕捉”。。。将这行代码插入catch块

抛出新异常（例如Message）

并去掉

返回的结果这将使您更好地理解错误（这次请不要忘记与我们分享错误）