Here is a simple openfiledialog filter

Tech Talk vb.Net
1 

Dim myStream As Stream 
    Dim openFileDialog1 As New OpenFileDialog() 
        
    openFileDialog1.InitialDirectory = "c:\" 
    openFileDialog1.Filter = "txt files (*.txt)/*.txt/All files (*.*)/*.*" 
    openFileDialog1.FilterIndex = 2 
    openFileDialog1.RestoreDirectory = True