The LA Fox Developer Newsletter

January 1998

Hot Tip...

Easy Way for Read/Write

of .ini Files

To access and change ini files you can use low-level file 10 and

there are probably other such ways, but one of the eaiest ways

to get and write data to .ini files is to use windows API calls.

GetProfileSection, GetProflleString, WriteProfileString. Here is

a sample use of these functions:

declare GetProfileString in win32api string,string,string,

string @,integer

declare WriteProfileString in win32api string,string,string

declare GetProfileSection in win32api string,string @,integer

**

the following example will read the available printer names

read the name of the default printer

**

and change the default printer to the first name on the list

**

NOTES : to change the active printer in VFP

--

it is much easier to get all the printer names using

**

APRINTERS() and than using SET PRINTER TO NAME

**

windowprintername but the printer section is common

**

to most users and this way most ppl can see this example

work - this .ini file change of the default printer will not

**

affect win95 users since win95 uses the registry to store

--

this info. This change in the ini file will not take affect

--

until you either restart windows or issue a

**

SendMessage (another API call) to all active windows

with a change in ini file msg

[WM_WININICHANGE (=26)]

The first parameter s the section name, the second

parameter is the buffer the last parameter is the length

*

of the buffer . don’t specify something bigger than the

**

space you allocated to the buffer or you’ll get the infamous

“error 6 tying to report error 6” error (which means “You

managed to smear my memory - now what?”)

IcBuffer=space(1000)

=GetProfileSection(”PrinterPorts”,@lcBuffer,lOOO)

this will get single line from the ini file, in this case the default

**

printer name: the first param is Section name, the second is

**

the item name, the third parameter “stam” is a default string

**

to return if no such line exists. Again, the 4th and last para-

**

meters are the buiffer and Its length.

lcDefaultPrinter=space(50)

=GetProfileString("windows","device","stam",@c,50)

lnTempl=atc(”,”,lcBuffer,3)-1

lnTemp2=arc(char(O),lcBuffer).1

IcNewPrinter=left(lcBuffer,llt(InTemp2>InTempl ,lnTempl ,lnTemp2)

=WriteProfileString(”windows” ,“device”,lcNewPrinter)

VFP Codebook for Mere

Mortals Update

from Kevin McNiesh

Here is a list of the major changes included in the latest release

of VFP Codebook for Mere Mortals. Each of these changes plus

many more are listed in the “What’s New” document and

Developers Guide that comes with the framework.

Integration with Stonefield Database Toolkit

In this release we have provided integration with Stonefield

Database Toolkit. We have created a new “Stonefield” compo-

nent class that you can add to your application object when you

want to integrate with Stonefield Database Toolkit. This

Stonefleld class is a subclass of our new Component class

which will be used in the future to integrate with other 3rd Party

Products.

Greater Flexibility

We have added a greater degree of flexibility to the framework

by means of our new Abstract Factory. This new class opens

up the framework by allowing you to specify the concrete class

names of the major framework components. This makes it very

easy to replace components in the framework with your own

custom classes.

For example, if you would like to replace the Mere Mortals error

handier with your own error handler class, you can simply

specify the name of the alternate error handler class in our new

“Classes” table and the framework will take care of the rest. If

you are not familiar with the Abstract Factory pattern, check out

the book Design Patterns: Elements of Reusable Object-

Oriented Software by Gamma, Helm, Johnson & Vlissides.

New Business Rules Class

Introduced the concept of a business rules class that can be

attached to a business object. Breaking out business rules from

the business object allows you to subclass and specialize

business rules. For example, your application may require

different business rules for different users. User I may be

allowed to override a customer’s credit limit up to $10,000

whereas User 2 may only be allowed an override of up to

$5,000.

The framework does not require that you use a separate busi-

ness rules class, but offers the option where needed.

Support for External Class Libraries

Join

LA Fox

In VFP 5, a new “IN” clause was added to the SET CLASSLIB

command which allows you to access class libraries in an .app

or .exe file outside of your main application. We have added

support for external class libraries in our Abstract Factorj

metadata table. You can specify that the framework use a

particular class in a specific .exe or .app file.

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