WebClient通过代理服务器访问网页

            {
                WC = new System.Net.WebClient();
                //实例化代理服务器对象
                WebProxy myProxy = new WebProxy(@"http://192.168.0.1:8080",true);
                // 设置用户帐号username,password
                myProxy.Credentials = new NetworkCredential("username", "password");
                // 为WebClient设置proxy
                WC.Proxy  = myProxy;
                s = WC.OpenRead(url);
                sr = new System.IO.StreamReader(s);
                CodeSource = sr.ReadToEnd();
                sr.Close();
                sr.Dispose();
                s.Close();
                s.Dispose();
            }
            catch (Exception ex)
            {
                if (ex.Message.ToString().Contains("401"))
                    MessageBox.Show("Web Access denied (Unauthorized)");
                else
                    MessageBox.Show(ex.Message);
            }
            finally
            {
                WC.Dispose();