ตัวอย่างการทำระบบ Login เอง ใน Win App ด้วย VB.NET

Public Class MyPrincipal
    Implements System.Security.Principal.IPrincipal
    Dim _objIden As MyIdentity

    Public ReadOnly Property Identity As System.Security.Principal.IIdentity Implements System.Security.Principal.IPrincipal.Identity
        Get
            Return Me._objIden
        End Get
    End Property

    Public Function IsInRole(ByVal role As String) As Boolean Implements System.Security.Principal.IPrincipal.IsInRole
        If Me._objIden.IsAuthenticated Then
            If role = "Administrators" Then Return True
        End If
        Return False
    End Function

    Public Sub New()
        Me._objIden = New MyIdentity()
    End Sub
End Class

Public Class MyIdentity
    Implements System.Security.Principal.IIdentity

    Private _UserName As String

    Public Function Login(ByVal UserName As String, ByVal pwd As String) As Boolean
        If UserName = "Admin" And pwd = "hello" Then
            Me._UserName = UserName
            Return True
        Else
            Return False
        End If
    End Function

    Public ReadOnly Property AuthenticationType As String Implements System.Security.Principal.IIdentity.AuthenticationType
        Get
            Return "MyType"
        End Get
    End Property

    Public ReadOnly Property IsAuthenticated As Boolean Implements System.Security.Principal.IIdentity.IsAuthenticated
        Get
            If Me._UserName <> "" Then
                Return True
            Else
                Return False
            End If
        End Get
    End Property

    Public ReadOnly Property Name As String Implements System.Security.Principal.IIdentity.Name
        Get
            Return Me._UserName
        End Get
    End Property
End Class

Imports System.Windows.Forms

Public Class MDIParent1

    Private Sub MDIParent1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        My.User.CurrentPrincipal = New MyPrincipal
        CType(My.User.CurrentPrincipal.Identity, MyIdentity).Login("Admin", "hello")

        Dim st As String = ""
        st = "User Name: " & My.User.Name
        st &= vbCrLf & "Is in Administrators: " & My.User.IsInRole("Administrators")
        st &= vbCrLf & "Is in Lovers: " & My.User.IsInRole("Lovers")
        MessageBox.Show(st)
    End Sub
End Class