Can't get HttpContext.Current.User.Identity to

Question

I want to capture the user opening my page in an internal Windows AD network.

I think I've tried everything:

@{
// other code
string user123 = HttpContext.Current.User.Identity;
}

and also

@{
// other code
<script>
    var user123 = HttpContext.Current.User.Identity;
</script>
}

And trying to use that later inside my HTML code. Or passing it as a parameter to a stored procedure inside my razor block.

Nothing. Either empty, runtime error, or undefined.

Note1: HttpContext is recognized by WebMatrix as an element.

Note2: I enabled Windows Authentication in the server.

Note3: My head is spinning from this.

Note4: I'm a total rookie, as I'm just getting started with this.

Note5: I tried Page.Current... but it doesn't recognize the Page element.