Sub TestFileOpen()

  ' Local variable declarations
  Dim strFile

  ' Let the user pick a 3dm file. If the return value is null,
  ' then the user picked the "Cancel" button...
  strFile = Rhino.OpenFileName("Open", "Rhino 3D Models (*.3dm)|*.3dm|")
  If IsNull(strFile) Then Exit Sub

  ' To keep Rhino from displaying the dreaded
  ' "Save changes to <filename>" dialog, we can fool it
  ' into thinking that the document was never modified
  ' by doing the following.
  Call Rhino.DocumentModified(False)

  ' If the picked a file that has a space character in its name,
  ' or resides in a folder that has a space character, then we
  ' need to surround the file string in double-quotes so Rhino's
  ' command line parser will interpret the string correctly.
  strFile = Chr(34) & strFile & Chr(34)

  ' Now we can simply script Rhino's Open command to open the file.
   Call Rhino.Command("_-Open " & strFile, 0)

End Sub