Wt Dialog Widgets

Wt supports modal and non-modal dialogs. There are four classes involved in dialogs:

WDialog

a widget that displays contents within a window drawn on top of the screen. Any widget can be inserted in a dialog.

WMessageBox

a dialog that contains only a single line of text and some configurable buttons. It is convenient to use this class if you only have to display a simple message.

Ext::Dialog

The ExtJs implementation of a dialog.

Ext::MessageBox

The ExtJs implementation of a message box.

Dialogs can be used in two ways. The traditional method, borrowed from desktop GUI toolkits, involves calling exec(). This starts a local event loop which returns when the dialog is closed. While this method is convenient and familiar, it usually does not scale for web applications, as every session displaying a dialog keeps a thread occupied for an extended period of time. This may not be a problem if you plan to deploy every user session in its own process, but otherwise sessions will stall as the server runs out of threads. The scalable alternative to the local event loop is not to invoke is to simply show() the dialog similar to what you would do with any other widget, and delete when the finished() signal is triggered.