vb.net REG限時試用功能 [Beta system limit]

Imports Microsoft.Win32

    Dim dteRegLock As DateTime = "2015/12/15"
    Dim strRegName As String = "ArtisCalcBeta"

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        If DemoVersion() = False Then
            Me.Opacity = 0
            Me.ShowInTaskbar = False
            Timer1.Enabled = True

        End If
    End Sub

    Private Function DemoVersion() As Boolean
        Dim regKey As RegistryKey
        regKey = Registry.LocalMachine.OpenSubKey("SOFTWARE\\SmallGCOk", True)
        Dim strKey As String = regKey.GetValue(strRegName)
        If strKey = "" Then
            regKey.SetValue(strRegName, Date.Today.ToString("yyyy/MM/dd"))
        Else
            Dim dteTemp As Date
            Try
                dteTemp = Date.Parse(strKey)
                If (dteTemp.DayOfYear + 30) < Date.Today.DayOfYear Or Date.Today > dteRegLock Then
                    MsgBox("試用期已過期，請聯絡SmallGCOk，購買正版", 16, "錯誤")
                    Return False
                End If
            Catch ex As Exception

            End Try
        End If

        Return True
    End Function

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        End
    End Sub