在Winform中发HTTP请求(调用WebService服务)

手工发送HTTP请求主要是调用System.NET的HttpWEBResponse方法

　　手工发送HTTP的GET请求:
   string strURL = "http://localhost/Play/CH1/Service1.asmx/doSearch?keyword=";
   strURL +=this.textBox1.Text;
   System.NET.HttpWEBRequest request;
   //创建一个HTTP请求.
   request = (System.NET.HttpWebRequest)WEBRequest.Create(strURL);
   //request.Method="get";
   System.NET.HttpWEBResponse response;
   response = (System.NET.HttpWEBResponse)request.GetResponse();
   System.IO.Stream s;
   s = response.GetResponseStream();
   XmlTextReader Reader = new XMLTextReader(s);
   Reader.MoveToContent();
   string strValue = Reader.ReadInnerXML();
   strValue = strValue.Replace("&lt;","<");
   strValue = strValue.Replace("&gt;",">");

   MessageBox.Show(strValue); 
   Reader.Close();

　　手工发送HTTP的POST请求
   string strURL = "http://localhost/Play/CH1/Service1.asmx/doSearch";
   System.NET.HttpWEBRequest request;
   
   request = (System.NET.HttpWebRequest)WEBRequest.Create(strURL);
   //Post请求方式
   request.Method="POST";
   //内容类型
   request.ContentType="application/x-www-form-urlencoded";
   //参数经过URL编码
   string paraUrlCoded = System.WEB.HttpUtilITy.UrlEncode("keyword");
   paraUrlCoded += "=" + System.WEB.HttpUtilITy.UrlEncode(this.textBox1.Text);
   byte[] payload;
   //将URL编码后的字符串转化为字节
   payload = System.Text.Encoding.UTF8.GetBytes(paraUrlCoded);
   //设置请求的ContentLength 
   request.ContentLength = payload.Length;
   //获得请求流
   Stream wrITer = request.GetRequestStream();
   //将请求参数写入流
   writer.WrITe(payload,0,payload.Length);

   //关闭请求流
   wrITer.Close();
   System.NET.HttpWEBResponse response;
   //获得响应流
   response = (System.NET.HttpWEBResponse)request.GetResponse();
   System.IO.Stream s;
   s = response.GetResponseStream();
   XmlTextReader Reader = new XMLTextReader(s);
   Reader.MoveToContent();
   string strValue = Reader.ReadInnerXML();
   strValue = strValue.Replace("&lt;","<");
   strValue = strValue.Replace("&gt;",">");
   MessageBox.Show(strValue); 
   Reader.Close();

　　Get请求与Post请求的主要区别在于Post的参数要经过URL编码并在获得请求之前传送,而Get把参数用URL编码后直接附加到请求的URL后面URL编码是一种字符编码格式,它确保传递的参数由一致的文本组成(如将空格编码为"%20")