Uri.MakeRelative tells the difference between two Uri instances.
Imports System.IO
Imports System.Net
Imports System.Text
publicclass MainClass
Shared Sub Main()
Dim address1 As New Uri("http://www.yourDomain.com/")
Dim address2 As New Uri("http://www.yourDomain.com/index.htm?date=today")
Console.WriteLine("The difference is {0}", address1.MakeRelativeUri(address2))
End Sub
End Class