Global and local variable

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Help / WLanguage / WLanguage syntax / Declaring variables

Overview
Global variable
Variables global to a project
Variables global to a window
Variables global to a report
Variables global to a set of procedures
How to use a global variable from a component
Global Variable: Syntax
Declaring one or more global variables
Local variable
Local variable: Syntax
Declaring one or more local variables
Zombie local and global variables

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Global and local variable

Overview

Two types of variables are available:

Local variable: can only be used in the process in which this variable has been declared.
Global variable: can be used in all processes depending on the process in which this variable has been declared.

Important: Do not declare two variables with the same name (in particular, a global variable and a local variable).

Global variable

Variables global to a project

Global variables declared in the "Initialization" event of a project can be used in all the events or processes:

of the project.
of the window or page (events of the window or page, of its controls and of the associated local procedures).
of the report (events of the report, of its controls and of the associated local procedures).

Variables global to a window

Global variables declared in the "Global declarations" event of a window can be used in all the events or processes:

of the window.
of the window controls.
of the local procedures associated with the window.

Limits:

The global variables of a window cannot be used by its sibling windows.
The global variables declared in a child window cannot be used in its parent window.
When the window where the variable was declared is closed, this variable cannot be used anymore.

Note: Use of a global variable in a child window of thedeclaration window.

The variables declared global in a window are visible in the child windows of this window in the following cases:

If the External keyword is used to declare the variable in the child window.
If the variable name is prefixed by the window name.
If the variable is passed as a parameter to the child window.

Variables global to a report

Global variables declared in the "Open" event of a report can be used in all the events or processes:

of the report.
of the report controls.
of the local procedures associated with the report.

Variables global to a set of procedures

Global variables declared in the "Declaration" event of a set of procedures can be used in all the events or processes:

of the different procedures in the set.
of the current project.

How to use a global variable from a component

Since the purpose of a component is to be stand-alone, no global variable of the project should be used from this one.

However, the recommended method is as follows:

create a global variable in the component.
in the component, create a procedure used to initialize these global variables.
from the "Initialization" event of the project and whenever the value of the global variables of the project is modified, call this procedure to assign a similar value to the global variables of the component.

Global Variable: Syntax

Declaring one or more global variables

GLOBAL
<Variables globales>

Details of syntax


GLOBAL	Beginning of declaration of global variables.
<Global variables>	Global variables to declare.

GLOBAL // Toutes les déclarations qui suivent sont des variables globales
Indice is int
NomClient is string
Taux is real

LOCAL // Toutes les déclarations qui suivent sont des variables locales
I is int 
PrénomClient is string
Prix is currency

Local variable

Local variables can only be used in the events or processes in which they are declared. Outside of these events or processes, local variables are unknown. These variables cannot be shared by several events or processes.

By default, a variable is local when it is declared.

Local variable: Syntax

Declaring one or more local variables

[LOCAL]
<Variables locales>

Details of syntax


LOCAL	Beginning of declaration of local variables. The LOCAL keyword is optional.
<Local variables>	Local variables to declare.

LOCAL // Toutes les déclarations qui suivent sont des variables locales
I is int
PrénomClient is string 
Prix is currency

// Toutes les déclarations qui suivent sont des variables locales
I is int
PrénomClient is string 
Prix is currency

Zombie local and global variables

A local or global variable can become obsolete. This allows you to in know that this element must not be used anymore (but that it is not deleted yet).

To declare a variable as being obsolete, all you have to do is use the <Zombie> extension attribute.

The syntax is as follows:

In this syntax, the optional comment keyword is used to specify the text that will be displayed in the compilation error associated with the obsolete variable.

Example:

PrénomClient is string <zombie commentaire = "Ne plus utiliser - utiliser la structure Client">