DooM Wad level name viewer

Hi this is the starting point of my to be WAD tool for doom this class allows you to show all the lump names in the main doom.wad file.
Comments and suggestions welcome.

Class code cWad.cs

vbnet Code:

Imports System.IO
Imports System.Text
 
Public Class cWad
 
    Public LumpNames As List(Of String)
 
    Public Sub LoadWad(ByVal Filename As String)
        Dim br As BinaryReader = Nothing
        Dim Counter As Integer = 0
 
        'Wad variables.
        Dim Sig As String = vbNullString
        Dim Lumps As Integer = 0
        Dim Offset As Integer = 0
        'Lump variables.
        Dim LumpAddr As Integer = 0
        Dim LumpSize As Integer = 0
        Dim LumpName As String = vbNullString
 
        'Open wad filename.
        br = New BinaryReader(File.OpenRead(Filename))
        'Get header sig should be IWAD
        Sig = Encoding.ASCII.GetString(br.ReadBytes(4))
 
        'Check for vaild wad sig
        If Not Sig.Equals("IWAD") Then
            Throw New ArgumentException("No Vaild IWAD Header Found")
            Exit Sub
        End If
 
        'Read number of lumps and lump start offset.
        Lumps = br.ReadInt32
        Offset = br.ReadInt32
 
        'Create new lump names list.
        LumpNames = New List(Of String)
 
        'Seek to Offset
        br.BaseStream.Seek(Offset, SeekOrigin.Begin)
 
        While( Counter < Lumps)
            'Read lump offset and lump size.
            LumpAddr = br.ReadInt32
            LumpSize = br.ReadInt32
            'Get lump name.
            LumpName = Encoding.ASCII.GetString(br.ReadBytes(8)).Replace(Chr(0), "")
            'Add lump name to list
            LumpNames.Add(LumpName)
            'INC Counter
            Counter += 1
        End While
        'Close file.
        br.Close()
    End Sub
End Class

Example showing level names.

vbnet Code:

Dim WadFile As New cWad
 
        Try
            'Load wad filename.
            WadFile.LoadWad("C:\out\data\DOOM.WAD")
 
            ListBox1.Items.Clear()
            'This sniplet below adds all the doom level names to a listbox.
            For Each Item As String In WadFile.LumpNames
                If Item.StartsWith("E") And Char.IsDigit(Item(1)) Then
                    ListBox1.Items.Add(Item)
                End If
            Next Item
 
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Sub