1、不带参数的POST请求

public static string Post(string url) 
{ 
  string result = ""; 
  HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url); 
  req.Method = "POST"; 
  HttpWebResponse resp = (HttpWebResponse)req.GetResponse(); 
  Stream stream = resp.GetResponseStream(); 
  //获取内容 
  using (StreamReader reader = new StreamReader(stream, Encoding.UTF8)) 
  { 
    result = reader.ReadToEnd(); 
  } 
  return result; 
} 

2、带参数的POST请求

public static string Post(string url,Dictionary<string,string> dic) 
{ 
  string result = ""; 
  HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url); 
  req.Method = "POST"; 
  req.ContentType = "application/x-www-form-urlencoded"; 
  #region 添加Post 参数 
  StringBuilder builder = new StringBuilder(); 
  int i = 0; 
  foreach (var item in dic) 
  { 
    if (i > 0) 
      builder.Append("&"); 
    builder.AppendFormat("{0}={1}", item.Key, item.Value); 
    i++; 
  } 
  byte[] data = Encoding.UTF8.GetBytes(builder.ToString()); 
  req.ContentLength = data.Length; 
  using (Stream reqStream = req.GetRequestStream()) 
  { 
    reqStream.Write(data, 0, data.Length); 
    reqStream.Close(); 
  } 
  #endregion 
  HttpWebResponse resp = (HttpWebResponse)req.GetResponse(); 
  Stream stream = resp.GetResponseStream(); 
  //获取响应内容 
  using (StreamReader reader = new StreamReader(stream, Encoding.UTF8)) 
  { 
    result = reader.ReadToEnd(); 
  } 
  return result; 
} 

3、不带参数的GET请求

public static string Get(string url) 
{ 
  string result = ""; 
  HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url); 
  HttpWebResponse resp = (HttpWebResponse)req.GetResponse(); 
  Stream stream = resp.GetResponseStream(); 
  try 
  { 
    //获取内容 
    using (StreamReader reader = new StreamReader(stream)) 
    { 
      result = reader.ReadToEnd(); 
    } 
  } 
  finally 
  { 
    stream.Close(); 
  } 
  return result; 
} 

4、带参数的GET请求

public static string Get(string url, Dictionary<string, string> dic) 
{ 
  string result = ""; 
  StringBuilder builder = new StringBuilder(); 
  builder.Append(url); 
  if (dic.Count > 0) 
  { 
    builder.Append("?"); 
    int i = 0; 
    foreach (var item in dic) 
    { 
      if (i > 0) 
        builder.Append("&"); 
      builder.AppendFormat("{0}={1}", item.Key, item.Value); 
      i++; 
    } 
  } 
  HttpWebRequest req = (HttpWebRequest)WebRequest.Create(builder.ToString()); 
  //添加参数 
  HttpWebResponse resp = (HttpWebResponse)req.GetResponse(); 
  Stream stream = resp.GetResponseStream(); 
  try 
  { 
    //获取内容 
    using (StreamReader reader = new StreamReader(stream)) 
    { 
      result = reader.ReadToEnd(); 
    } 
  } 
  finally 
  { 
    stream.Close(); 
  } 
  return result; 
} 

5、自定义HTTP请求头

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url); 
req.Method = "GET"; 
req.Headers["Accept-Language"] = "zh-CN,zh;q=0.8"; 
req.Referer = "https://www.baidu.com/"; 
HttpWebResponse resp = (HttpWebResponse)req.GetResponse(); 
Stream stream = resp.GetResponseStream(); string result = 【本文由：http://www.1234xp.com/cdn.html 提供,感谢支持】""; //注意，此处使用的编码是：gb2312 //using (StreamReader reader = new StreamReader(stream, Encoding.Default)) using (StreamReader reader = new StreamReader(stream, Encoding.GetEncoding("gb2312"))) 
{ 
  result = reader.ReadToEnd(); 
}