Question

我正在尝试对某个服务器进行异步调用，以便主线程不会因请求而停止。

我创建了这样的请求：

//Create Request
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);
        request.Method = method;
        request.ContentType = "application/XML";

        System.Text.UTF8Encoding encoding = new System.Text.UTF8Encoding();
        byte[] bytes = encoding.GetBytes(data);

        request.ContentLength = bytes.Length;

        try
        {
            using (Stream requestStream = request.GetRequestStream())
            {
                // Send the data.
                requestStream.Write(bytes, 0, bytes.Length);
            }

            request.BeginGetResponse((x) =>
            {
                using (HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(x))
                {
                    if (callback != null)
                    {
                        callback(response.GetResponseStream());
                    }
                }
            }, null);
        }
        catch (Exception ex)
        {
            //TODO: Log error
        }

但是线程在此请求中仍然会停止一段时间。特别是在线上使用

(Stream requestStream = request.GetRequestStream())

我们有什么方法可以使它完全异步或其他更好的方式，以便我们的主线程不会挂起此请求。

Answer 1

using (HttpClient client = new HttpClient())
{
    var content = new StringContent(data, Encoding.UTF8, "application/xml");
    var response = await client.PostAsync(uri, content);
    var respString = await response.Content.ReadAsStringAsync();
}

Answer 2

需要使用异步方法并等待它们。

using (var stream = await request.GetRequestStreamAsync())
{
    await stream.WriteAsync(bytes, 0, bytes.Length);
}

Answer 3

这是一个简单的示例，我用它来制作异步请求。使用async keyword

标记您的方法

using (var httpClient = new HttpClient())
{
    string requestContent = string.Empty; // JSON Content comes here
    HttpContent httpContent = new StringContent(requestContent, Encoding.UTF8, "application/json");
    HttpRequestMessage httpRequestMessage = new HttpRequestMessage(Verb, url);
    httpRequestMessage.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    httpRequestMessage.Content = request.Verb == HttpMethod.Get ? null : httpContent;
    response = httpClient.SendAsync(httpRequestMessage);
    var responseContent = await response.Result.Content.ReadAsStringAsync();

}

c＃异步http请求

3 个答案: