ListExtension

Function ListFileExtensions() As String()
Dim regKeys As Collection
Dim regKey As Variant
Dim extsNdx As Long
Dim progID As String
Dim clsid As String

Const HKEY_CLASSES_ROOT = &H80000000

' retrieve all the subkeys under HKEY_CLASSES_ROOT

Set regKeys = EnumRegistryKeys(HKEY_CLASSES_ROOT, "")

' prepare the array of results

ReDim exts(3, regKeys.Count) As String

' ignore errors

On Error Resume Next

For Each regKey In regKeys
' check whether this is a File extension

If Left$(regKey, 1) = "." Then
' store the extension in the result array

extsNdx = extsNdx + 1
exts(0, extsNdx) = regKey
' the default value for this key is the ProgID

' or another string that can be searched in the Registry

progID = GetRegistryValue(HKEY_CLASSES_ROOT, regKey, "")
exts(1, extsNdx) = progID
' the default value of the key HKEY_CLASSES_ROOT\ProgID is

' the textual description of this entry

exts(2, extsNdx) = GetRegistryValue(HKEY_CLASSES_ROOT, progID, "")
If exts(2, extsNdx) = "" Then
' if this key doesn't exist, delete this entry

extsNdx = extsNdx - 1
Else
' else try to read the location of the associated EXE file

exts(3, extsNdx) = GetRegistryValue( _
HKEY_CLASSES_ROOT, progID & "\shell\open\command", "")
End If
End If
Next

' trim unused items

ReDim Preserve exts(3, extsNdx) As String
ListFileExtensions = exts()
End Function
this is a VB6-only routine
return a bi-dimension string array, where
arr(0, i) is the file extension
arr(1, i) is the coresponding ProgID
arr(2, i) is the associated description
arr(3, i) is the location of the executable file

Example:
' fill a listbox with descriptions associated to each

' registered file extension

Dim a() As String, i As Long
a() = ListFileExtensions()
For i = 1 To UBound(a, 2)
List1.AddItem a(0, i) & vbTab & a(2, i)
Next

NOTE: requires the EnumRegistryKey and GetRegistryValue functions
available on VB-2-The-Max's Code Bank