Problema para conectar con clase BD en visual Basic

[serenimusmoriarty]

Hola!!
muchas gracias por tu respuesta,

bueno hice lo que me dijiste:

Código:

 Private Sub ButtonVerCategorias_Click(sender As Object, e As EventArgs) Handles ButtonVerCategorias.Click
        'Dim mibase As New BaseDatos
        Dim mibase As BaseDatos = New BaseDatos()
        Dim listaCat As New ArrayList


        Try
            BaseDatos.abrirBase()
            listaCat = BaseDatos.listarCategorias(mibase)

            For i As Integer = 0 To listaCat.Count
                ListBoxCategorias.Items.Add(listaCat(i))

            Next

            BaseDatos.cerrarBase()


        Catch ex As OleDbException

        End Try

    End Sub
End Class

pero me dió el mismo error de NullReferenceException...no se
si me pudes dar alguna otra idea te voy a dejar la cadena de conexion
ya aprovecho y te pongo un copia y pega de la clase BaseDatos:

Código:

Imports System.Data.OleDb
Imports System.Collections.ArrayList


Public Class BaseDatos

    'Dim conexion As OleDbConnection
    Private Shared conexion As OleDbConnection
    Private Shared comado As OleDbCommand
    Private Shared cadenaConexion As String


    Public Sub New(ByVal BaseDatos As String)
        Dim cadenaConexion As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\muebles.accdb"
        ' cadenaConexion = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Users\mario\Documents\Visual Studio 2012\Projects\Muebles_DAW\Muebles_DAW\muebles.accdb"
        conexion = New OleDbConnection(cadenaConexion)

    End Sub
    Public Sub New()

    End Sub

    Public Shared Function abrirBase() As Boolean

        Try
            conexion.Open()


        Catch ex As Exception

        End Try
        Return False
    End Function

    Public Shared Function cerrarBase() As Boolean

        Try
            conexion.Close()
            Return True




        Catch ex As OleDbException
            Return False



        End Try
    End Function


    Public Shared Function listarCategorias(ByVal mibase As BaseDatos) As ArrayList
        Dim cat As New ArrayList()
        Dim cadena As String = "SELECT codigo,nombre_categoria FROM categorias"
        Try
            'conexion.Open()
            comado = New OleDbCommand(cadena, conexion)
            Dim registros As OleDbDataReader = comado.ExecuteReader
            While (registros.Read())

                cat.Add(registros.GetInt16("codigo"))
                cat.Add(registros.GetString("nombre_categoria"))


            End While
            Return cat
            'conexion.Close()


        Catch ex As Exception

        End Try


    End Function


End Class

Gracias de nuevo y ...Feliz Año!!