Problem when checking for valid filetype

Hello, I'm using the code below to check how many valid avi videos there are in a folder.

Every time a valid avi video has been found, 1 should be counted up (ct). This works fine if there are only valid avi videos in the folder, but if I rename a mp3 audio file to .avi and put that file in the folder with the valid avi videos, then ct always returns "0".

Does anybody know what is wrong?

VB Code:

Public Function GetFileType(xFile As String) As String
    On Error Resume Next
    Dim ID As String * 300
 
    Open xFile For Binary Access Read As #1
    Get #1, 1, ID
    Close #1
    GetFileType = Mid(ID, 9, 8)
End Function
 
 
 
Private Sub cmdCheck_Click()
  Dim ct As Integer
  Dim a As String
  Dim Valid_type As String
 
  ct = 0
  a = sPath & Dir(sPath & "*.avi")
  Valid_type = GetFileType(a)
  
  Do While LenB(a) > LenB(sPath)
    
    If Valid_type = "AVI LIST" Then
    ct = ct + 1
    End If
    
    a = sPath & Dir
  Loop
 
Msgbox ct
 
End Sub

You are checking the File type only once, so it will return only one. Try this instead:

VB Code:

Private Sub cmdCheck_Click()
  Dim ct As Integer
  Dim a As String
  Dim Valid_type As String
 
  ct = 0
  a = sPath & Dir(sPath & "*.avi")
 
  
  Do While LenB(a) > LenB(sPath)
    [b]Valid_type = GetFileType(a) [/b]   
    If Valid_type = "AVI LIST" Then
    ct = ct + 1
    End If
    
    a = sPath & Dir
  Loop
 
Msgbox ct
 
End Sub

Yes, that works fine. Thank you for your help :)