实现代码

开头需要引用System.IO，System.Net两个命名空间。

using System.IO;
using System.Net;

GET请求

//此处自定义函数HttpGet
public static string HttpGet(string url)
        {
            Encoding encoding = Encoding.UTF8;//编码方式，此处为UTF-8
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);//创建Http请求
            request.Method = "GET";//请求方法，此处为GET
            request.Accept = "text/html, application/xhtml+xml, */*";//媒体类型
            request.ContentType = "application/json";//JSON数据格式
            request.Timeout = 20000;//超时时间,以毫秒为单位
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();//发送请求
            using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
            {
                return reader.ReadToEnd();//返回数据
            }
        }

POST请求

//此处自定义函数HttpPost
public static string HttpPost(string url)
        {
            Encoding encoding = Encoding.UTF8;//编码方式，此处为UTF-8
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);//创建Http请求
            request.Method = "Post";//请求方法，此处为GET
            request.Accept = "text/html, application/xhtml+xml, */*";//媒体类型
            request.ContentType = "application/json";//JSON数据格式
            request.Timeout = 20000;//超时时间,以毫秒为单位
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();//发送请求
            using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
            {
                return reader.ReadToEnd();//返回数据
            }
        }

调用函数

上面的代码是定义了用于发送请求的函数，在实际使用中还需要调用自定义的函数来实现，当然你也可以不定义函数直接使用。

        //函数名("URL" + 参数);
        string a = 1;
        string b = HttpGet("http://www.xxx.com/api.php?a=" + a);