When you return error information from a class module, you must be aware that
some special handling is required. If you want to generate a certain numbered error in a class
module, you should add a constant number, vbObjectError (a number in the range of negative two billion
on most systems), to your error number before you invoke the Raise method. You should do this
to signal the error is generated in the class object but raised to the calling routine or
application.
If you wanted to raise error number 500 in your class module, for example,
you would invoke the Err.Raise method and pass vbObjectError + 500 as the error number. The
calling program or module interpreting the runtime error generated by the Raise method should then
strip off the vbObjectError constant to interpret your error.
NOTE - Error Numbers That You Can Use: Currently
not all the numbers between 0 and 66,535 are being used by Visual Basic. Some
of the numbers are used; others are being reserved for future use. Using the vbObjectError
enables you to define your own error numbers. It also prevents rewrite in the
future—when later versions of Visual Basic that use more error numbers are
released.
