C#模拟http 发送post或get请求

private string HttpPost(string Url, string postDataStr)

        
{
            
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);
            
request.Method = 
"POST"
;
            
request.ContentType = 
"application/x-www-form-urlencoded"
;
            
request.ContentLength = Encoding.UTF8.GetByteCount(postDataStr);
            
request.CookieContainer = cookie;
            
Stream myRequestStream = request.GetRequestStream();
            
StreamWriter myStreamWriter = 
new 
StreamWriter(myRequestStream, Encoding.GetEncoding(
"gb2312"
));
            
myStreamWriter.Write(postDataStr);
            
myStreamWriter.Close();  
            
HttpWebResponse response = (HttpWebResponse)request.GetResponse();  
            
response.Cookies = cookie.GetCookies(response.ResponseUri);
            
Stream myResponseStream = response.GetResponseStream();
            
StreamReader myStreamReader = 
new 
StreamReader(myResponseStream, Encoding.GetEncoding(
"utf-8"
));
            
string 
retString = myStreamReader.ReadToEnd();
            
myStreamReader.Close();
            
myResponseStream.Close();  
            
return 
retString;
        
}  
        
public 
string 
HttpGet(
string 
Url, 
string 
postDataStr)
        
{
            
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url + (postDataStr == 
"" 
? 
"" 
: 
"?"
) + postDataStr);
            
request.Method = 
"GET"
;
            
request.ContentType = 
"text/html;charset=UTF-8"
;  
            
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            
Stream myResponseStream = response.GetResponseStream();
            
StreamReader myStreamReader = 
new 
StreamReader(myResponseStream, Encoding.GetEncoding(
"utf-8"
));
            
string 
retString = myStreamReader.ReadToEnd();
            
myStreamReader.Close();
            
myResponseStream.Close();  
            
return 
retString;
        
}  

在post的时候有时也用的到cookie，像登录163发邮件时候就需要发送cookie，所以在外部一个cookie属性随时保存 CookieContainer cookie = new CookieContainer();

！注意：有时候请求会重定向，但我们就需要从重定向url获取东西，像QQ登录成功后获取sid，但上面的会自动根据重定向地址跳转。我们可以用:
request.AllowAutoRedirect = false;设置重定向禁用，你就可以从headers的Location属性中获取重定向地址