提问



如何使用POST方法发出HTTP请求并发送一些数据?
我可以GET请求,但不知道如何制作POST

最佳参考


有几种方法可以执行HTTP GETPOST请求:





方法A:HttpClient


适用于:.NET Framework 4.5 +,.NET Standard 1.1 +,.NET Core 1.0+


目前首选的方法。异步。通过NuGet提供的其他平台的便携版本。[28]


using System.Net.Http;


设置


建议为您的应用程序的生命周期实例化HttpClient并分享它。[29]


private static readonly HttpClient client = new HttpClient();


POST


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 = await response.Content.ReadAsStringAsync();


GET


var responseString = await client.GetStringAsync("http://www.example.com/recepticle.aspx");





方法B:第三方库


RestSharp [30]


经过试验和测试的库,用于与REST API交互。便携。可通过NuGet获得。[31]


Flurl.Http [32]


较新的图书馆提供流畅的API和测试助手。引擎盖下的HttpClient。便携。可通过NuGet获得。[33]


using Flurl.Http;


POST


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


GET


var responseString = await "http://www.example.com/recepticle.aspx"
    .GetStringAsync();





方法C:遗产


适用于:.NET Framework 1.1 +,.NET Standard 2.0 +,.NET Core 1.0+


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


POST


var request = (HttpWebRequest)WebRequest.Create("http://www.example.com/recepticle.aspx");

var postData = "thing1=hello";
    postData += "&thing2=world";
var data = Encoding.ASCII.GetBytes(postData);

request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
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(现在也是旧版)


适用于:.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");
}

其它参考1


简单的GET请求


using System.Net;

...

using (var wb = new WebClient())
{
    var response = wb.DownloadString(url);
}


简单的POST请求


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

...

using (var wb = new WebClient())
{
    var data = new NameValueCollection();
    data["username"] = "myUser";
    data["password"] = "myPassword";

    var response = wb.UploadValues(url, "POST", data);
    string responseInString = Encoding.UTF8.GetString(response);
}

其它参考2


MSDN有一个样本。[34]


using System;
using System.IO;
using System.Net;
using System.Text;

namespace Examples.System.Net
{
    public class WebRequestPostExample
    {
        public static void Main()
        {
            // Create a request using a URL that can receive a post. 
            WebRequest request = WebRequest.Create("http://www.contoso.com/PostAccepter.aspx");
            // Set the Method property of the request to POST.
            request.Method = "POST";
            // Create POST data and convert it to a byte array.
            string postData = "This is a test that posts this string to a Web server.";
            byte[] byteArray = Encoding.UTF8.GetBytes(postData);
            // Set the ContentType property of the WebRequest.
            request.ContentType = "application/x-www-form-urlencoded";
            // Set the ContentLength property of the WebRequest.
            request.ContentLength = byteArray.Length;
            // Get the request stream.
            Stream dataStream = request.GetRequestStream();
            // Write the data to the request stream.
            dataStream.Write(byteArray, 0, byteArray.Length);
            // Close the Stream object.
            dataStream.Close();
            // Get the response.
            WebResponse response = request.GetResponse();
            // Display the status.
            Console.WriteLine(((HttpWebResponse)response).StatusDescription);
            // Get the stream containing content returned by the server.
            dataStream = response.GetResponseStream();
            // Open the stream using a StreamReader for easy access.
            StreamReader reader = new StreamReader(dataStream);
            // Read the content.
            string responseFromServer = reader.ReadToEnd();
            // Display the content.
            Console.WriteLine(responseFromServer);
            // Clean up the streams.
            reader.Close();
            dataStream.Close();
            response.Close();
        }
    }
}

其它参考3


这是以JSON格式发送/接收数据的完整工作示例,我使用的是VS2013 Express Edition


using System;
using System.Collections.Generic;
using System.Data;
using System.Data.OleDb;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using System.Web.Script.Serialization;

namespace ConsoleApplication1
{
    class Customer
    {
        public string Name { get; set; }
        public string Address { get; set; }
        public string Phone { get; set; }
    }

    public class Program
    {
        private static readonly HttpClient _Client = new HttpClient();
        private static JavaScriptSerializer _Serializer = new JavaScriptSerializer();

        static void Main(string[] args)
        {
            Run().Wait();
        }

        static async Task Run()
        {
            string url = "http://www.example.com/api/Customer";
            Customer cust = new Customer() { Name = "Example Customer", Address = "Some example address", Phone = "Some phone number" };
            var json = _Serializer.Serialize(cust);
            var response = await Request(HttpMethod.Post, url, json, new Dictionary<string, string>());
            string responseText = await response.Content.ReadAsStringAsync();

            List<YourCustomClassModel> serializedResult = _Serializer.Deserialize<List<YourCustomClassModel>>(responseText);

            Console.WriteLine(responseText);
            Console.ReadLine();
        }

        /// <summary>
        /// Makes an async HTTP Request
        /// </summary>
        /// <param name="pMethod">Those methods you know: GET, POST, HEAD, etc...</param>
        /// <param name="pUrl">Very predictable...</param>
        /// <param name="pJsonContent">String data to POST on the server</param>
        /// <param name="pHeaders">If you use some kind of Authorization you should use this</param>
        /// <returns></returns>
        static async Task<HttpResponseMessage> Request(HttpMethod pMethod, string pUrl, string pJsonContent, Dictionary<string, string> pHeaders)
        {
            var httpRequestMessage = new HttpRequestMessage();
            httpRequestMessage.Method = pMethod;
            httpRequestMessage.RequestUri = new Uri(pUrl);
            foreach (var head in pHeaders)
            {
                httpRequestMessage.Headers.Add(head.Key, head.Value);
            }
            switch (pMethod.Method)
            {
                case "POST":
                    HttpContent httpContent = new StringContent(pJsonContent, Encoding.UTF8, "application/json");
                    httpRequestMessage.Content = httpContent;
                    break;

            }

            return await _Client.SendAsync(httpRequestMessage);
        }
    }
}

其它参考4


您需要使用WebRequest类和GetRequestStream方法。


这是一个例子。[35]

其它参考5


到目前为止我发现的简单(单行,无错误检查,无需等待响应)解决方案


(new WebClient()).UploadStringAsync(new Uri(Address), dataString);‏


谨慎使用!

其它参考6


使用 Windows.Web.Http 命名空间时,对于POST而不是FormUrlEncodedContent,我们编写HttpFormUrlEncodedContent。响应也是HttpResponseMessage的类型。其余的是Evan Mulawski写下来的。