using proxy with com webbrower C#

public void strproxy(string serverName,string port)
{
string key = "Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings";
string proxy = serverName + ":" + port;
RegistryKey RegKey = Registry.CurrentUser.OpenSubKey(key, true);
RegKey.SetValue("ProxyServer", proxy);
RegKey.SetValue("ProxyEnable", 1);
}
button click
string strurl = "http://shimivn.blogspot.com";
webBrowser1.Url =new System.Uri(strurl);
webBrowser1.Document.Cookie = null;
webBrowser1.GoForward
// webBrowser1.Show();