C#调用HTTP接口

string url = "http://www.***.com?id=123&username=test&userpwd=*****";
WebRequest wRequest = WebRequest.Create(url);
wRequest.Method = "GET";
wRequest.ContentType = "text/html;charset=UTF-8";
WebResponse wResponse = wRequest.GetResponse();
Stream stream = wResponse.GetResponseStream();
StreamReader reader = new StreamReader(stream, System.Text.Encoding.Default);
string str = reader.ReadToEnd();   //url返回的值
reader.Close();
wResponse.Close();