Private Sub MvcApplication_PostAuthenticateRequest(sender As Object, e As EventArgs) Handles Me.PostAuthenticateRequest

        Dim IdentityId As String = Context.User.Identity.IdentityId
        Dim IdentityName As String = Context.User.Identity.IdentityName
        Dim FirstName As String = Context.User.Identity.FirstName
        Dim LastName As String = Context.User.Identity.LastName
        Dim Email As String = Context.User.Identity.Email

        Dim CurrentPrincipal As New CustomWindowsPrincipal(DirectCast(User.Identity, WindowsIdentity), employee)

        HttpContext.Current.User = CurrentPrincipal

    End Sub

Imports System.Runtime.CompilerServices
Imports System.Security.Claims
Imports System.Security.Principal

<Extension>
Public Module IdentityExtension

    Private _UserPrincipal As UserPrincipal
    Private _ClaimsIdentity As ClaimsIdentity
    Private _PrincipalContext As PrincipalContext

    Private _fullname As String
    Private _identityid As String
    Private _identityname As String
    Private _firstname As String
    Private _lastname As String
    Private _email As String

    <Extension>
    Public Function FullName(obj As IIdentity) As String

        If _fullname <> Nothing Then
            Return _fullname
        End If

        If _ClaimsIdentity Is Nothing Then
            _ClaimsIdentity = TryCast(obj, ClaimsIdentity)
        End If

        If _ClaimsIdentity Is Nothing Then
            Return Nothing
        End If

        If _PrincipalContext Is Nothing Then
            _PrincipalContext = New PrincipalContext(ContextType.Domain, "MYDOMAIN", Nothing, ContextOptions.Negotiate)
        End If

        If _PrincipalContext Is Nothing Then
            Return Nothing
        End If

        If _UserPrincipal Is Nothing Then
            _UserPrincipal = UserPrincipal.FindByIdentity(_PrincipalContext, IdentityType.SamAccountName, _ClaimsIdentity.Name)
        End If

        If _UserPrincipal Is Nothing Then
            Return Nothing
        End If

        _fullname = String.Format("{0} {1}", _UserPrincipal.GivenName, _UserPrincipal.Surname)

        Return _fullname

    End Function

etc...

Imports System.Security.Principal

Public Class CustomWindowsPrincipal
    Inherits WindowsPrincipal

    Public ReadOnly Property Employee As Employee

    Public Sub New(CurrentWindowsIdentity As WindowsIdentity, EmployeeParam As Employee)
        MyBase.New(CurrentWindowsIdentity)
        Employee = EmployeeParam
    End Sub

    Public Overrides Function IsInRole(role As String) As Boolean

        If Employee Is Nothing Then
            Return False
        End If

        If Employee.Roles.Count = 0 Then
            Return False
        End If

        If Employee.Roles.Where(Function(p) p.Name = role).Count = 0 Then
            Return False
        End If

        Return True

    End Function

End Class

Public Module IdentityExtension

Dim _UserPrincipal As UserPrincipal = UserPrincipal.FindByIdentity(_PrincipalContext, IdentityType.SamAccountName, _ClaimsIdentity.Name)

Imports System.Runtime.CompilerServices
Imports System.Security.Claims
Imports System.Security.Principal

<Extension>
Public Module IdentityExtension

    <Extension>
    Public Function FullName(obj As IIdentity) As String

        Dim _ClaimsIdentity As ClaimsIdentity = TryCast(obj, ClaimsIdentity)

        If _ClaimsIdentity Is Nothing Then
            Return Nothing
        End If

        Dim _PrincipalContext As PrincipalContext = New PrincipalContext(ContextType.Domain, "MYDOMAIN", Nothing, ContextOptions.Negotiate)

        If _PrincipalContext Is Nothing Then
            Return Nothing
        End If

        Dim _UserPrincipal As UserPrincipal = UserPrincipal.FindByIdentity(_PrincipalContext, IdentityType.SamAccountName, _ClaimsIdentity.Name)

        If _UserPrincipal Is Nothing Then
            Return Nothing
        End If

        Return String.Format("{0} {1}", _UserPrincipal.GivenName, _UserPrincipal.Surname)

    End Function
End Module