To raise our own errors using the
Err.Raise method, we need error numbers
that do not conflict with those used by Visual Basic. The Visual
Basic documentation says that error numbers in the range
+ 65535, where
a built-in constant whose value is the signed integer
as an unsigned hexadecimal integer), are designed to signal an error
generated by an object.
It further says that error numbers below
512 may conflict with values reserved for OLE, so
these numbers are verboten. Thus, we are left
with numbers in the range
65535, which should be plenty.
Many programmers like to assign symbolic constants to error numbers, since it tends to improve readability and cut down on the need for comments. For instance, we could add the line:
Public Const ErrBadDataCt = vbObjectError + 1024
in a standard module.