如何使用HttpClient发布数据？

Question

我有来自Nuget的this HttpClient。

当我想获取数据时，我这样做：

var response = await httpClient.GetAsync(url);
var data = await response.Content.ReadAsStringAsync();

但问题是我不知道如何发布数据？我必须发送一个帖子请求并在其中发送这些值：comment="hello world"和questionId = 1。这些可以是一个类的属性，我不知道。

更新我不知道如何将这些值添加到HttpContent，因为post方法需要它。 httClient.Post(string, HttpContent);

Answer 1

你需要使用：

await client.PostAsync(uri, content);

像这样的东西：

var comment = "hello world";
var questionId = 1;

var formContent = new FormUrlEncodedContent(new[]
{
    new KeyValuePair<string, string>("comment", comment), 
    new KeyValuePair<string, string>("questionId", questionId) 
});

var myHttpClient = new HttpClient();
var response = await myHttpClient.PostAsync(uri.ToString(), formContent);

如果您需要在发布后获得响应，您应该使用：

var stringContent = await response.Content.ReadAsStringAsync();

希望能帮助到你 ;）

Answer 2

试着用这个：

            using (var handler = new HttpClientHandler() { CookieContainer = new CookieContainer() })
            {
                using (var client = new HttpClient(handler)
                { BaseAddress = new Uri("site.com") })
                {
                    //add parameters on request
                    var body = new List<KeyValuePair<string, string>>
                    {
                        new KeyValuePair<string, string>("test", "test"),
                        new KeyValuePair<string, string>("test1", "test1")
                    };

                    HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, "site.com");

                    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/x-www-form-urlencoded; charset=UTF-8"));
                    client.DefaultRequestHeaders.Add("Upgrade-Insecure-Requests", "1");
                    client.DefaultRequestHeaders.Add("X-Requested-With", "XMLHttpRequest");
                    client.DefaultRequestHeaders.Add("X-MicrosoftAjax", "Delta=true");
                    //client.DefaultRequestHeaders.Add("Accept", "*/*");

                    client.Timeout = TimeSpan.FromMilliseconds(10000);

                    var res = await client.PostAsync("", new FormUrlEncodedContent(body));

                    if (res.IsSuccessStatusCode)
                    {
                        var exec = await res.Content.ReadAsStringAsync();
                        Console.WriteLine(exec);
                    }                    
                }
            }

Answer 3

使用UploadStringAsync方法：

        WebClient webClient = new WebClient();
        webClient.UploadStringCompleted += (s, e) =>
            {
                if (e.Error != null)
                {
                    //handle your error here
                }
                else
                {
                    //post was successful, so do what you need to do here
                }

            };


        webClient.UploadStringAsync(new Uri(yourUri), UriKind.Absolute), "POST", yourParameters);