The page contexts

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The pages

The page contexts

Overview

In a Windows application, the information relative to a window is stored with the window.

In a dynamic WEBDEV site, a page context exists on the server for each page displayed on the browser of Web user.

The page context groups the information about the page:

content of controls,
local variables,
global variables,
WLanguage "server" code, ...

Operating mode

Automatic management

By default, WEBDEV automatically manages the contexts of dynamic pages:

A page context is opened when the dynamic page is displayed in the browser.
The context of a page is updated according to the information typed by the Web user in the browser. This update is performed when validating the page (via a "Submit" button or with PageSubmit).
The existing page contexts are closed when using PageUse or FramesetUse. Then, the page contexts corresponding to the pages to display are opened.

Advanced management

WEBDEV allows you to perform an advanced management of contexts via the ContextXXX functions.

You can:

open the page context without displaying it on the browser (ContextOpen),
check the existence of a page context on the server (ContextExist),
close the context of an unused page (ContextClose).

This advanced management of page contexts can be used to:

Save memory on the server (by closing the contexts of pages previously opened but unused for example).
Prepare the pages intended to communicate with other applications (the page receiving information back from a site for secure payment for example).
Use the pages from other pages.

Special case

When using the browser "Back" button, a desynchronization may occur between the page and its context. See Managing the browser "Back" button. for more details