I have just begun to to learn how to write macros in VC++.   For learning
purposes, I would like to implement a macro that accesses all files in a
'test' project and makes a series of changes to these files.  I am able to
identify each file in my project and then open the file.  But I have yet to
figure out how to close the file.  Could someone kindly tell me how to close
a file?  The following BASIC code illustrates my first efforts:

Sub replaceMacro()
   Dim oItems As ProjectItems = DTE.ActiveSolutionProjects(0).ProjectItems
   Dim oI As ProjectItem
   For Each oI In oItems
           Dim oFilename As String = oI.Name()
           oI.Open(vsViewKindPrimary)

           ' close file
           '   the following line fails and generates the error message
           '  "Object reference not set to an instance of an object
           DTE.ActiveDocument.Close(vsSaveChanges.vsSaveChangesYes)
   Next
End Sub

thanks in advance

Ian