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("<","<");
strValue = strValue.Replace(">",">");
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("<","<");
strValue = strValue.Replace(">",">");
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")