如果你喜欢一个流畅的API，你可以使用Tiny.RestClient。在NuGet上可以买到。

var client = new TinyRestClient(new HttpClient(), "http://MyAPI.com/api");
// POST
var city = new City() { Name = "Paris", Country = "France" };
// With content
var response = await client.PostRequest("City", city)
                           .ExecuteAsync<bool>();

还有另一种做法:

using (HttpClient httpClient = new HttpClient())
using (MultipartFormDataContent form = new MultipartFormDataContent())
{
    form.Add(new StringContent(param1), "param1");
    form.Add(new StringContent(param2), "param2");
    using (HttpResponseMessage response = await httpClient.PostAsync(url, form))
    {
        response.EnsureSuccessStatusCode();
        string res = await response.Content.ReadAsStringAsync();
        return res;
    }
}

通过这种方式，您可以轻松地发布一个流。

执行HTTP GET和POST请求有几种方法:

---

方法A: HttpClient(首选)

支持。net Framework 4.5+， . net Standard 1.1+， . net Core 1.0+。

它是目前首选的方法，并且是异步的和高性能的。在大多数情况下使用内置版本，但对于非常老的平台，有一个NuGet包。

using System.Net.Http;

设置

建议为应用程序的生命周期实例化一个HttpClient并共享它，除非您有特定的理由不这样做。

private static readonly HttpClient client = new HttpClient();

请参阅HttpClientFactory以获得依赖注入解决方案。

---

帖子 var values = new Dictionary<string, string> ｛ {"thing1"， "hello"}， {"thing2"， "world"} }; var content = new FormUrlEncodedContent(values); var response = await client.PostAsync("http://www.example.com/recepticle.aspx"， content); var responseString =等待response.Content.ReadAsStringAsync(); 得到 var responseString = await client.GetStringAsync("http://www.example.com/recepticle.aspx");

---

方法B:第三方库

休息夏普

帖子 var client = new RestClient("http://example.com"); / /客户端。Authenticator =新的HttpBasicAuthenticator(用户名，密码); var request = new RestRequest("resource/{id}"); 请求。AddParameter(“thing1”、“你好”); 请求。AddParameter(“事件”、“世界”); 请求。AddHeader(“标题”、“价值”); 请求。AddFile(“文件”,路径); var response = client.Post(请求); var content = response.Content;//原始内容为字符串 var response2 = client.Post<Person>(request); var name = response2.Data.Name;

Flurl。Http

它是一个更新的库，拥有一个流畅的API，测试助手，在底层使用HttpClient，并且是可移植的。它可以通过NuGet获得。

    using Flurl.Http;

---

帖子 var responseString = await“http://www.example.com/recepticle.aspx” .PostUrlEncodedAsync(new {thing1 = "hello"， thing2 = "world"}) .ReceiveString (); 得到 var responseString = await“http://www.example.com/recepticle.aspx” .GetStringAsync ();

---

方法C: HttpWebRequest(不推荐用于新工作)

支持。net Framework 1.1+， . net Standard 2.0+， . net Core 1.0+。在。net Core中，它主要是为了兼容性——它包装了HttpClient，性能较差，并且不会获得新的特性。

using System.Net;
using System.Text;  // For class Encoding
using System.IO;    // For StreamReader

---

发布 var request = （HttpWebRequest）WebRequest.Create（“http://www.example.com/recepticle.aspx”）; var postData = “thing1=” + Uri.EscapeDataString（“hello”）; postData += “&thing2=” + Uri.EscapeDataString（“world”）; var data = Encoding.ASCII.GetBytes（postData）; 请求。方法 =“开机自检”; 请求。ContentType = “application/x-www-form-urlencoded”; 请求。内容长度 = 数据。长度; 使用 （var 流 = 请求。GetRequestStream（）） { 流。写入（数据， 0， 数据.长度）; } var response = （HttpWebResponse）request.获取响应（）; var responseString = new StreamReader（response.GetResponseStream（））。ReadToEnd（）; 获取 var request = （HttpWebRequest）WebRequest.Create（“http://www.example.com/recepticle.aspx”）; var response = （HttpWebResponse）request.获取响应（）; var responseString = new StreamReader（response.GetResponseStream（））。ReadToEnd（）;

---

方法D: WebClient(不推荐新作品)

这是一个HttpWebRequest的包装器。与HttpClient比较。

支持。NET Framework 1.1+， NET Standard 2.0+和。NET Core 2.0+。

在某些情况下…NET Framework 4.5-4.8)，如果你需要同步地做一个HTTP请求，WebClient仍然可以使用。

using System.Net;
using System.Collections.Specialized;

---

帖子 使用(var client = new WebClient()) ｛ var values = new NameValueCollection(); 值["thing1"] = "hello"; Values ["thing2"] = "world"; var response = client.UploadValues("http://www.example.com/recepticle.aspx"， values); var responseString = Encoding.Default.GetString(response); } 得到 使用(var client = new WebClient()) ｛ var responseString = client.DownloadString("http://www.example.com/recepticle.aspx"); }

为什么这不是完全无关紧要的?执行请求并不是处理结果。而且似乎还涉及到一些。net Bug——参见HttpClient中的Bug。GetAsync应该抛出WebException，而不是TaskCanceledException

我最终得到了这样的代码:

static async Task<(bool Success, WebExceptionStatus WebExceptionStatus, HttpStatusCode? HttpStatusCode, string ResponseAsString)> HttpRequestAsync(HttpClient httpClient, string url, string postBuffer = null, CancellationTokenSource cts = null) {
    try {
        HttpResponseMessage resp = null;

        if (postBuffer is null) {
            resp = cts is null ? await httpClient.GetAsync(url) : await httpClient.GetAsync(url, cts.Token);

        } else {
            using (var httpContent = new StringContent(postBuffer)) {
                resp = cts is null ? await httpClient.PostAsync(url, httpContent) : await httpClient.PostAsync(url, httpContent, cts.Token);
            }
        }

        var respString = await resp.Content.ReadAsStringAsync();
        return (resp.IsSuccessStatusCode, WebExceptionStatus.Success, resp.StatusCode, respString);

    } catch (WebException ex) {
        WebExceptionStatus status = ex.Status;
        if (status == WebExceptionStatus.ProtocolError) {
            // Get HttpWebResponse so that you can check the HTTP status code.
            using (HttpWebResponse httpResponse = (HttpWebResponse)ex.Response) {
                return (false, status, httpResponse.StatusCode, httpResponse.StatusDescription);
            }
        } else {
            return (false, status, null, ex.ToString());
        }

    // https://devblogs.microsoft.com/dotnet/net-5-new-networking-improvements/
    } catch (TaskCanceledException ex) when (ex.InnerException is TimeoutException) {
        return (false, ex.ToString(), null, WebExceptionStatus.Timeout);

    } catch (TaskCanceledException ex) {
        return (false, ex.ToString(), null, WebExceptionStatus.RequestCanceled);

    } catch (Exception ex) {
        return (false, WebExceptionStatus.UnknownError, null, ex.ToString());
    }
}

这将根据postBuffer是否为空来执行GET或POST操作。

如果Success为true，响应将在ResponseAsString中。

如果Success为false，你可以检查WebExceptionStatus, HttpStatusCode和ResponseAsString，看看哪里出了问题。

c# . net

    using System.Net.Http;
    
    private static readonly HttpClient httpClient = new HttpClient();

//POST    
    var values = new Object();
    values[0] = "Value1";
    values[2] = "Value2";
    values[n] = "ValueN";

    var content = new FormUrlEncodedContent(values);
    var response = await httpClient.PostAsync("URL", content);
    var responseString = await response.Content.ReadAsStringAsync();

    

//GET
 var response = await httpClient.GetStringAsync("URL");

这个解决方案只使用标准的. net调用。

测试:

在企业WPF应用程序中使用。使用async/await来避免阻塞UI。 兼容。net 4.5+。 在没有参数的情况下进行测试(在幕后需要一个“GET”)。 使用参数进行测试(需要幕后的“POST”)。 使用标准的网页(如谷歌)进行测试。 使用内部基于java的web服务进行测试。

参考:

// Add a Reference to the assembly System.Web

代码:

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using System.Web;

private async Task<WebResponse> CallUri(string url, TimeSpan timeout)
{
    var uri = new Uri(url);
    NameValueCollection rawParameters = HttpUtility.ParseQueryString(uri.Query);
    var parameters = new Dictionary<string, string>();
    foreach (string p in rawParameters.Keys)
    {
        parameters[p] = rawParameters[p];
    }

    var client = new HttpClient { Timeout = timeout };
    HttpResponseMessage response;
    if (parameters.Count == 0)
    {
        response = await client.GetAsync(url);
    }
    else
    {
        var content = new FormUrlEncodedContent(parameters);
        string urlMinusParameters = uri.OriginalString.Split('?')[0]; // Parameters always follow the '?' symbol.
        response = await client.PostAsync(urlMinusParameters, content);
    }
    var responseString = await response.Content.ReadAsStringAsync();

    return new WebResponse(response.StatusCode, responseString);
}

private class WebResponse
{
    public WebResponse(HttpStatusCode httpStatusCode, string response)
    {
        this.HttpStatusCode = httpStatusCode;
        this.Response = response;
    }
    public HttpStatusCode HttpStatusCode { get; }
    public string Response { get; }
}

不带参数调用(在幕后使用“GET”):

 var timeout = TimeSpan.FromSeconds(300);
 WebResponse response = await this.CallUri("http://www.google.com/", timeout);
 if (response.HttpStatusCode == HttpStatusCode.OK)
 {
     Console.Write(response.Response); // Print HTML.
 }

使用参数调用(在幕后使用“POST”):

 var timeout = TimeSpan.FromSeconds(300);
 WebResponse response = await this.CallUri("http://example.com/path/to/page?name=ferret&color=purple", timeout);
 if (response.HttpStatusCode == HttpStatusCode.OK)
 {
     Console.Write(response.Response); // Print HTML.
 }