Imports Microsoft.AspNet.Identity
Imports Microsoft.Owin
Imports Microsoft.Owin.Security.Cookies
Imports Owin

<Assembly: OwinStartup(GetType(WebFormsIdentity.Startup))>
Namespace WebFormsIdentity
    Public Class Startup
        Public Sub Configuration(ByVal app As IAppBuilder)
            app.UseCookieAuthentication(New CookieAuthenticationOptions With {
                .AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
                .LoginPath = New PathString("~/UserArea")
            })
        End Sub
    End Class
End Namespace

Imports Microsoft.AspNet.Identity
Imports Microsoft.AspNet.Identity.EntityFramework
Imports Microsoft.Owin.Security
Imports System
Imports System.Web
Imports System.Web.UI.WebControls

Public Class UserArea
    Inherits System.Web.UI.Page

    Private Sub UserArea_Load(sender As Object, e As EventArgs) Handles Me.Load

        If Not IsPostBack Then

            If User.Identity.IsAuthenticated Then
                StatusText.Text = String.Format("Helo! {0}!!", User.Identity.GetUserName())
                loginStatus.Visible = True
                LogoutButton.Visible = True
            Else
                LoginForm.Visible = True
            End If

        End If
    End Sub

    Protected Sub SignIn(ByVal sender As Object, ByVal e As EventArgs)
        Dim userStore = New UserStore(Of IdentityUser)()
        Dim userManager = New UserManager(Of IdentityUser)(userStore)
        Dim user = userManager.Find(UserName.Text, Password.Text)

        If user IsNot Nothing Then
            Dim authenticationManager = HttpContext.Current.GetOwinContext().Authentication
            Dim userIdentity = userManager.CreateIdentity(user, DefaultAuthenticationTypes.ApplicationCookie)
            authenticationManager.SignIn(New AuthenticationProperties() With {
                        .IsPersistent = False
                    }, userIdentity)
            Response.Redirect("~/UserArea.aspx")
        Else
            StatusText.Text = "Invalid username or password."
            loginStatus.Visible = True
        End If
    End Sub

HttpContext.Current.GetOwinContext().Authentication