The LA Fox Developer Newsletter

April 1997

The previous diagram illustrates the classes of an employee

business object that utilizes polymorphism. Utilizing this format,

an entire payroll can be accomplished with very few lines of

code as shown in the following example:

Example Employee Business Object using VFP:

SET CLASSLIB TO ‘mynew.vcx’

oEmployee = CREATEOBJECT(’employee’

ocompanyState = CREATEOBJECT(oEmployee.State)

USE employee

SCAN

oEmp = CREATEOBJECT(ALLTRIM(employee.title))

=oEmployee.CalcPay(oEmp,oCompanyState)

RELEASE oEmp

ENDSCAN

USE

RELEASE oCompanyState

RELEASE oState

RELEASE oEmpioyee

The main class, Employee, defines the four methods, CalcPay,

CalcGross, CalcFed, CalcState.

CalcPay is the main method that calls the other three methods

before returning the final payroll figures. It receives as a param-

eter, an instance of the employee type object, either Hourly,

Salary, or Commission and the specific state object for the

company.

The CalcGross methods exist in the subclasses of Employee,

Hourly, Salary, and Commission where specific methods for

calculating GrossPay are located. It is this method that returns

the GrossPay back to the Employee.CalcPay method.

The CalcFed is located in the Employee object since all em-

ployees calculate federal tax the same way. It returns the

FederalTax back to the CalcPay method of the Employee class.

For one client, the code for CalcState could be in the Employee

object. This however limits the reusability of the Employee

object. Instead, by creating a State class, with the calculations

for that state payroll tax as a method, new states can be added

by merely creating additional objects. These objects, would

then pass the calculated state tax back to the

Employee.CalcPay method.

(Con’t, page 8)

Hot Tip

How to Change the

Mouse Cursor

by Arnon Gal-Oz

Virtual FoxPro User Group

This tip shows u how to change the mouse cursor to any cursor

shape you desire.

**

these are the WIN32API functions u need for changinf the

**

mouse cursor

declare integer LoadCursorFromFile in win32api as NewCur string

declare short SetSystemCursor in win32api Integer ,integer

*NORMAL

32512 - usually u would put these in a .h file

*IBEAM

32513

*WAIT

32514

*CROSS

32515

*UP

32516

*SIZE

32640

*ICON

32641

*SIZENWSE

32642

*SIZENESW

32643

*SIZEWE

32644

*SIZENS

32645

*SIZEALL

32646

*ICOCUR

32647

*NO

32648 (Win NT only)

* get a handle for a new cursor

nCurHndl=NewCur(”c:~vfp\samples\graphics~cursors~down.cur”)

*

this example changes the norami (arrow) cursor to the new

cursor

*

u can use normal0l.cur to return to the normal cursor

nchangOK=SetSystemCursor(nCurHndl,3251 2)

*after u changed one of the “system” cursors to ur own

*u can use the MousePointer property to reference it

[Ed. Note: Arnon Gal-Oz is the Head of Computer Dept. of On

Time Serial Supply, an Israeli subscription seivices company.

He is also the President of the Israeli foxpro User Group, and

the Tehcnical Manager of the Virtual Foxpro User Group. If

you’re interested in joining this “virtual” group, you may do so by

visiting The Visual FoxPro Yellow Pages, at http:I/

www.transformation.com and filling out the membership applica-

tion. And best of all? It’s free!!]

Spring Conference

Vendors Announced

As you may know, we’ve added a fifth track to the conference

which will be reserved for vendors presenting their products, as

well as a Vendor Trade Show. Among vendors participating in

the sessions and trade show will be Micromega (Foxfire!), Kevin

McNeish (“Framework for Mere Mortals”P’Codebook for Mere

Mortals”), Roger Woodsmall (AutoManual), Doug Hennig

(Stonefield Data Dictionary), Drew Speedie/MaxTech (Visual

MaxFrame Professional), and xCase.

Business Objects (Con’t from page 3)

Page 5