Help with Accessing Shapefile in ArcObjects Dialog Box

[MichelleCouden1]

I wrote a program awhile back accessing a map document when the command Map button was clicked. I was wondering the commands to use for accessing a shapefile when the command Map button is clicked. For Example, for the document it is
Dim pDoc as IDocument
Dim pApp As IApplication
Set pDoc = New MxDocument
Set pApp = pDoc.Parent

Please help. Thanks!!

[DuncanHornby]

Are you asking to access a shapefile that is already loaded in the map document or as direct access to a dataset on some hard drive somewhere?