i successfully installed FriendlyUrl from Nuget using Install-Package Microsoft.AspNet.FriendlyUrls -Pre 
now I am trying to do this in my default page :
<a href="<%: FriendlyUrl.Href("~/About","Watch") %>">About.aspx</a> 
but this error occurred : 'FriendlyUrl' does not exist in the current context
how can I fix it ?
