从处理方法中返回值

Question

我有以下代码：

public class HttpRequestsHandler
    {
        public static T HttpGetWithContent<T>(string requestUrl)
        {
            using (var handler = new WebRequestHandler())
            {
                handler.ServerCertificateValidationCallback = (sender, certificate, chain, errors) => true;

                using (var httpClient = new HttpClient(handler)
                {
                    BaseAddress = new Uri(requestUrl),
                    Timeout = Timeout.InfiniteTimeSpan
                })
                {
                    using (var response = httpClient.GetAsync(requestUrl).Result)
                    {
                        if (response.StatusCode != HttpStatusCode.OK && response.StatusCode != HttpStatusCode.Gone)
                        {
                            var errorMessage = $"HttpRequestTask: Request failed with status {response.StatusCode} for URL: {requestUrl}";
                            throw new HttpException(errorMessage, (int)response.StatusCode);
                        }
                        return response.Content.ReadAsAsync<T>().Result;
                    }
                }
            }
        }
        public static T HttpGetWithContentWrapper<T>(string requestUrl)
        {
            return HttpGetWithContent<T>(requestUrl);
        }
  }

现在，当我称它为：

private void Button_Click(object sender, DoWorkEventArgs e)
    {
        var worker = new BackgroundWorker();
        worker.DoWork += (sender, args) =>
        {
            var url = UrlProvider.BuildRequestUrl();
            var date = HttpRequestsHandler.HttpGetWithContent<DateTime>(url);
            //More code...
        };
        worker.RunWorkerCompleted += (sender, args) =>
        {
           //more code...
        };
        worker.RunWorkerAsync();
    }

它就像一种魅力，但是当我使用包装方法时：

private void Button_Click(object sender, DoWorkEventArgs e)
    {
        var worker = new BackgroundWorker();
        worker.DoWork += (sender, args) =>
        {
            var url = UrlProvider.BuildRequestUrl();
            var date = HttpRequestsHandler.HttpGetWithContentWrapper<DateTime>(url); //fails here
            //More code...
        };
        worker.RunWorkerCompleted += (sender, args) =>
        {
           //more code...
        };
        worker.RunWorkerAsync();
    }

它以错误“无法访问的区域”结束。

现在我想这与我不熟悉的一次性模式有关。 据我了解，它用于应用程序中的非托管资源，因此对象仅位于“使用中”。

我不明白的是它如何在第一部分而不是第二部分中返回值...

谢谢，

UPDATE-我很抱歉，为了使代码能正常工作，我粘贴了错误的代码，然后将其更改为原始代码，这给我带来了麻烦，谢谢

Answer 1

尝试改变

public static T HttpGetWithContentWrapper<T>(string requestUrl)
{
    return HttpGetWithContent<T>(string requestUrl);
}

至

public static T HttpGetWithContentWrapper<T>(string requestUrl)
{
    return HttpGetWithContent<T>(requestUrl);
}

通过将string requestUrl编写为参数，可以有效地将空字符串传递给方法。 可能是导致错误的原因（假设此错误存在于您的实际代码中，而不仅仅是示例中）。