Browse Prior Art Database

Implementation of Comprehensive Qualification and Validation of Entry Fields

IP.com Disclosure Number: IPCOM000114898D
Original Publication Date: 1995-Feb-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 106K

Publishing Venue

IBM

Related People

Morgan, SA: AUTHOR [+4]

Abstract

Disclosed is a comprehensive application design for providing the default entry field qualification, validation and feedback that is needed in a graphical user interface.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Implementation of Comprehensive Qualification and Validation of Entry
Fields

      Disclosed is a comprehensive application design for providing
the default entry field qualification, validation and feedback that
is needed in a graphical user interface.

      The Presentation Manager* (PM) of OS/2* provides entry fields
for user input.  These entry fields will accept any character typed
in by the user.  Some entry fields, however, should be designed to
accept only particular characters and strings, based on the type of
data for which the entry field is meant.

      There are many such classes of input.  Entry fields can be
numeric only, and within that class be designed for a particular base
only, such as decimal or hexadecimal.  The numeric entry field might
allow numbers only within a specified range.  An entry field might
only allow alphabetic characters, with specific characters allowed
only in specific places within the string.  There are many such types
of qualification that could be desired.

      Given that an entry field might allow only qualified data to be
input, the user should be given immediate feedback when invalid input
is made.  An invalid character should not be allowed to be entered,
and invalid strings should be pointed out to the user at the earliest
possible moment.  The feedback provided to the user should be
specific as to the problem.

      In an object-oriented environment, the entry field itself will
have stored what type of qualification has been specified for it.
When qualification or validation is required, it knows what method or
function to call to perform the checks.

      To intercept keystrokes, the entry field must be subclassed and
the WM_CHAR message intercepted.  The parameters to this message
provide the information necessary to tell if the keystroke is a
character, and what character it is.

      For qualification types that only allow certain characters,
such as numeric only or alphabetic only, the individual character
should be screened at input time.  When the keystroke is received in
the entry field subclass, it can be compared against the allowable
characters for that class.  If it is an invalid character, the
subclass throws it away rather than passing it on the the default PM
message procedure to display.  The subclass also causes a beep to
sound to provide aural feedback to the user that an invalid character
was entered.  If it is a valid character, it is passed on to PM for
display in the entry field.

      Other qualification types are dependent on the entire string.
These include numeric fields that only allow numbers within a
specified range, or strings that have positional dependencies.  Since
the feedback of incorrect input should be provided to the user as
soon as possible, validation is performed on the entire stri...