VB - List All The Files In A Directory

[techker]

The Dir way :

'Just add a listbox (List1)
 
Private Sub ListFiles(strPath As String, Optional Extention As String)
'Leave Extention blank for all files
    Dim File As String
    
    If Right$(strPath, 1) <> "\" Then strPath = strPath & "\"
    
    If Trim$(Extention) = "" Then
        Extention = "*.*"
    ElseIf Left$(Extention, 2) <> "*." Then
        Extention = "*." & Extention
    End If
    
    File = Dir$(strPath & Extention)
    Do While Len(File)
        List1.AddItem File
        File = Dir$
    Loop
End Sub
 
Private Sub Form_Load()
ListFiles "C:\", "txt"
End Sub

why do i get errors?
i added a list box named it List1

Error 1 Optional parameters must specify a default value. C:\Users\TECHKER\Desktop\PROGRAMMING\PROJECTS\WindowsApplication1\WindowsApplication1\Form5.vb 3 74 WindowsApplication1

Error 2 'Public ReadOnly Property Right() As Integer' has no parameters and its return type cannot be indexed. C:\Users\TECHKER\Desktop\PROGRAMMING\PROJECTS\WindowsApplication1\WindowsApplication1\Form5.vb 7 12 WindowsApplication1

Error 4 'Public Property Left() As Integer' has no parameters and its return type cannot be indexed. C:\Users\TECHKER\Desktop\PROGRAMMING\PROJECTS\WindowsApplication1\WindowsApplication1\Form5.vb 11 16 WindowsApplication1

Error 5 Type character '$' does not match declared data type 'Integer'. C:\Users\TECHKER\Desktop\PROGRAMMING\PROJECTS\WindowsApplication1\WindowsApplication1\Form5.vb 11 16 WindowsApplication1

Error 6 'AddItem' is not a member of 'System.Windows.Forms.ListBox'. C:\Users\TECHKER\Desktop\PROGRAMMING\PROJECTS\WindowsApplication1\WindowsApplication1\Form5.vb 17 13 WindowsApplication1