有几种执行HTTP
GET和
POST请求的方法：
方法A：HttpClient（首选）
可用：
.NET framework 4.5+，
.NET Standard 1.1+，
.NET Core 1.0+。
目前，它是首选方法，并且具有异步性和高性能。在大多数情况下，请使用内置版本，但对于非常旧的平台，则提供了NuGet软件包。
using System.Net.Http;
设定
建议
HttpClient在应用程序的生命周期中实例化一个实例，并共享它，除非您有特殊原因不这样做。
private static readonly HttpClient client = new HttpClient();
请参阅
HttpClientFactory以获取依赖项注入解决方案。
POST
var values = new Dictionary<string, string>
{
{ “thing1”, “hello” },
{ “thing2”, “world” }
};var content = new FormUrlEnpredContent(values);
var response = await client.PostAsync("http://www.example.com/recepticle.aspx”, content);
var responseString = await response.Content.ReadAsStringAsync();
GET
var responseString = await client.GetStringAsync("http://www.example.com/recepticle.aspx");
方法B：第三方库
RestSharp
POST
var client = new RestClient("http://example.com");// client.Authenticator = new HttpBasicAuthenticator(username, password);
var request = new RestRequest(“resource/{id}”);
request.AddParameter(“thing1”, “Hello”);
request.AddParameter(“thing2”, “world”);
request.AddHeader(“header”, “value”);
request.AddFile(“file”, path);
var response = client.Post(request);
var content = response.Content; // Raw content as string
var response2 = client.Post(request);
var name = response2.Data.Name;
Flurl.Http
这是一个更新的库，具有流畅的API，测试助手，在后台使用HttpClient且可移植。可通过NuGet获得。
using Flurl.Http;
POST
var responseString = await "http://www.example.com/recepticle.aspx".PostUrlEnpredAsync(new { thing1 = "hello", thing2 = "world" }).ReceiveString();GET
var responseString = await "http://www.example.com/recepticle.aspx".GetStringAsync();
方法C：HttpWebRequest（不建议用于新工作）
可用：
.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-它可以包装
HttpClient，性能较低且不会获得新功能。
using System.Net;using System.Text; // For class Encodingusing System.IO; // For StreamReader
POST
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);request.Method = “POST”;
request.ContentType = “application/x-www-form-urlenpred”;
request.ContentLength = data.Length;using (var stream = request.GetRequestStream())
{
stream.Write(data, 0, data.Length);
}var response = (HttpWebResponse)request.GetResponse();
var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
GET
var request = (HttpWebRequest)WebRequest.Create("http://www.example.com/recepticle.aspx");var response = (HttpWebResponse)request.GetResponse();
var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
方法D：WebClient（不建议用于新工作）
这是一个包装
HttpWebRequest。与比较
HttpClient。
可在：
.NET framework 1.1+，
NET Standard 2.0+，
.NET Core 2.0+
using System.Net;using System.Collections.Specialized;
POST
using (var client = new WebClient())
{
var values = new NamevalueCollection();
values[“thing1”] = “hello”;
values[“thing2”] = “world”;var response = client.UploadValues("http://www.example.com/recepticle.aspx", values);var responseString = Encoding.Default.GetString(response);}
GET
using (var client = new WebClient())
{
var responseString = client.DownloadString("http://www.example.com/recepticle.aspx”);
}
