Form Concepts: Getting Started

As a user of AVEVA products, you will already be familiar with forms, and the gadgets (buttons, textboxes) on them.

The AVEVA software module which provides the ability for you to customize the AVEVA E3D graphical user interface using the PML is referred to as PML Forms and Menus (or just F&M).

The default 'system font' used by Forms and Menus to display character data is Arial Unicode MS which contains a large number of the world’s alphabets. Internally, Forms and Menus uses full Unicode, but can only display the characters accessible in its current 'system font'. You will be able to copy and paste Unicode characters from and to textual fields of Forms and Menus gadgets.

In PML 2, forms are a type of object represented by a Global variable - the name of the form, for example, !!EntryForm. This means that a form cannot have the same name as any other object type, Global variable, or any other form.

The form object owns a set of predefined member variables and built-in methods. In addition, you can define your own members (form variables and form gadgets) and your own form methods. All of these will determine the content and functionality of the form.

Gadget objects are User-defined members of the form object. Form members are always accessed using the dot notation, for example:

!!EntryForm.TextField

Gadgets own a set of predefined member variables and built-in methods which determine the content and functionality of the gadget. For example, the value of a text field gadget is accessed by:

!!EntryForm.TextField.val.

Note:
Gadgets do not support user-defined member variables or user-defined gadget methods.

Note:
All the in-built members and methods of forms and gadget-types are listed in the Software Customization Reference documentation.

Callbacks are User-defined actions assigned to a form and its gadgets and that are executed when the operator interacts with the form, for example, by clicking a mouse button on a gadget.

The callbacks are supplied as text strings and may be any valid PML expression, PML function, or PML method call, including any form, gadget or User-defined object method. Effectively, these callbacks determine the intelligence of the form.