Mastering PowerBuilder

No class library satisfies the customer exact needs. It has to be customized here and there. Our application isn’t an exception to this fact.

ever do any changes to any of the object that is residing in PFC libraries (Library name starts with PFC). Any customization has to be done in the extension layer libraries (Library name starts with PFE).

Invoke the n_cst_AppManager object from the PFEAPSRV.PBL library. All the event names, declared as part of PFC, start with "PFC". If you need to declare any user-defined event, name the event starting with "ue_". We need to initialize some attributes of the n_cst_AppManager object either by directly changing them or by calling methods. These attributes are used throughout the application. Write the following code to the Constructor event:

// Name of the application
iapp_object.DisplayName="Product Management System"

// Turning on the Microhelp functionality
of_SetMicroHelp (true)

// The file name of the application INI file
of_SetAppIniFile ("product.ini")

// PFC allows you using different files for the
// application and the user. We are using the same
// file for both purposes.
of_SetUserIniFile ("product.ini")

// PFC uses the registry if the registry is available.
// Application registry key
of_SetAppKey ("HKEY_LOCAL_MACHINE\Software\ASI\PMS")

// User registry key
of_SetUserKey ("HKEY_CURRENT_USER\Software\ASI\PMS")

// The file name of the application's online help file
//of_SetHelpFile ("pbpfc050.hlp")

// We don’t have any help file yet.
// The application version

of_SetVersion ("Version 1.0")

// The application logo (bitmap file name)
of_SetLogo ("asi.bmp")

// Application copyright message
of_SetCopyright ("Copyright @ 1996-99 Applied Software Inc")

// Wrapper property for application display name
is_title = iapp_object.DisplayName

All the above code is self-explanatory. If you run the application now, you will see a different login screen than the one we were using. However, you may not be able to login successfully. If you are using Windows ‘95/NT 4.0, you need to create the following registry entry:

HKEY_LOCAL_MACHINE\SOFTWARE\ASI\PMS

Click on the operating system Start button and select Run option. Type "RegEdit" and click OK. Operating system invokes the registry editor. In the left hand side, expand HKEY_LOCAL_MACHINE and then Software. Create an entry ASI (Applied Software Inc). Why we used our company name here? Because, every software company whose products are installed on your machine, has an entry under "Software". Under the company key, they have one entry for each of their software. Similarly, you need to create an entry to the "Product Management System", i.e., PMS.

Similarly create HKEY_CURRENT_USER\SOFTWARE\ASI\PMS entry. Under this, create one more registry key "logon". Under that create a string value "userid" and set it to "DBA".

Add the following entries to the product.ini file.

[Database]
DBMS=ODBC
Database=product
DBParm=ConnectString='DSN=product'

Write the following code to the "PFC_Open" event of the n_cst_AppManager object.

Integer li_rc
if of_IsRegistryAvailable() then
   sqlca.of_Init (of_GetUserKey() + "\PMS")
elseif sqlca.of_Init (is_userinifile, "Database") = -1 then
   MessageBox (is_title, "Initialization failed " + &
               "from file " + is_userinifile)
   halt
end if
Idle( 300 )

In the above code we are asking the PFC to read the key values that we specified in the of_SetUserKey() function in the "constructor" event of n_cst_AppManager. of_Init() function reads the values specified in the registry and sets the values in the transaction object. Now, we need to display the logon window to the user and accept his user id/password and log on to the database. PFC has a function of_LogonDlg() which does all that for you. Append the following code to the PFC_Open event of n_cst_AppManager object.

li_rc = gnv_app.of_LogonDlg()
IF li_rc <> 1 THEN
   MessageBox("Logon", "Logon failed")
   Halt Close
End If

open( w_mdi_frame )

You can call this function before you open the w_mdi_frame or you can open in the "open" event of the w_mdi_frame. Let’s choose the later method. We choose the former method.

Now, run the application and you should be able to login. You will see the same MDI window and menu that we are using till so far. Now, we need to create new windows and menus using the PFC objects. The next step would be creating a MDI window, and a menu using PFC classes.

Create a window by inheriting from w_frame (in the PFEMAIN.PBL). Change the window title to "Product Management System". Save the window as "w_mdi_frame".