vb的CommonDialog控件

我只想让里面显示的文件内容，显示到文件夹级别的，再下一层的，比如.doc等类似的就不显示了，应该怎样实现呢？单纯的就用此控件的相关属性进行控制能实现不？
请各位仔细的看清楚我的意思，我想实现的是只显示到文件夹这层，再下面层的文件不显示，一楼的恐怕误解了我的意思了，呵呵

不就是调用选择文件夹吗，用这个函数

Public Declare Function SHBrowseForFolder Lib "shell32.dll" Alias "SHBrowseForFolderA" (lpBrowseInfo As BROWSEINFO) As Long

Public Declare Function SHGetPathFromIDList Lib "shell32.dll" Alias "SHGetPathFromIDListA" (ByVal pidl As Long, ByVal pszPath As String) As Long

Public Type BROWSEINFO
hOwner As Long
pidlRoot As Long
pszDisplayName As String
lpszTitle As String
ulFlags As Long
lpfn As Long
lParam As Long
iImage As Long
End Type
Public Type SHITEMID
cb As Long
abID As Byte
End Type
Public Type ITEMIDLIST
mkid As SHITEMID
End Type

Function getFolder(frm As Form, Optional Flags As Long = 1) As String
On Error Resume Next
Dim BI As BROWSEINFO
Dim IDL As ITEMIDLIST
Dim r As Long