'  . IShellFolder::EnumObjects can return without validating the enumeration object  

static extern int EnumObjects(IntPtr hdc, int nObjectType, EnumObjectsProc

EnumObjectsProc

    void EnumObjects(

private delegate int EnumObjectsProc(IntPtr lpLogObject, IntPtr lParam);

Private Delegate Function EnumObjectsProc(ByVal lpLogObject As IntPtr, ByVal lParam As IntPtr) As Integer

     int EnumObjects([In, MarshalAs(UnmanagedType.U4)] int grfFlags, out IEnumUnknown ppenum);

     int EnumObjects([In, MarshalAs(UnmanagedType.U4)] int grfFlags, out IEnumUnknown ppenum);

    void EnumObjects(IntPtr hwnd, ESHCONTF grfFlags, out IntPtr ppenumIDList);