Try like this;
Uri.GetLeftPart( UriPartial.Authority )
Defines the parts of a URI for the Uri.GetLeftPart method.
http://www.contoso.com/index.htm?date=today --> http://www.contoso.com
http://www.contoso.com/index.htm#main --> http://www.contoso.com
nntp://news.contoso.com/[email protected] --> nntp://news.contoso.com
file://server/filename.ext --> file://server
Uri uriAddress = new Uri("http://www.contoso.com/index.htm#search");
Console.WriteLine("The path of this Uri is {0}", uriAddress.GetLeftPart(UriPartial.Authority));