Sub-dialog actions in procedural DIALOG blocks

This topic describes how action are differentiated with handlers defined in a procedural DIALOG block.

We distinguish dialog actions from sub-dialog actions. When the ON ACTION handler is defined at the same level as a BEFORE DIALOG control block, it is a dialog action, and the action name is a simple identifier as in singular interactive instructions:

action-name

When the ON ACTION handler is defined inside a sub-dialog, or if the action is an implicit action such as insert in INPUT ARRAY, it is a sub-dialog action. A sub-dialog action is qualified with the name of the sub-dialog:

sub-dialog-name.action-name

The INPUT ARRAY and DISPLAY ARRAY sub-dialogs are implicitly identified with the screen-record name defined in the form. For INPUT and CONSTRUCT sub-dialogs, the sub-dialog identifier can be specified with the NAME attribute.

This example defines two 'check' actions in different sub-dialog contexts, and a 'close' action at the dialog level:

DIALOG
  INPUT BY NAME ... ATTRIBUTES (NAME = "cust")
    ON ACTION check                   -- sub-dialog action "cust.check"
    ...
  END INPUT
  DISPLAY ARRAY arr_orders TO sr_ord.*
    ...
    ON ACTION check                   -- sub-dialog action "sr_ord.check"
    ...
  END DISPLAY
  BEFORE DIALOG
    ...
  ON ACTION close                      -- dialog action "close"
    ...
END DIALOG

By using the sub-dialog identifier in form definition files, you can bind action views to specific sub-dialog actions. Action views bound to sub-dialog actions with qualified sub-dialog action names will always be active, even if the focus is not in the sub-dialog of the action. You typically use fully-qualified sub-dialog action names for buttons in the form body or in topmenu options. However, it does not make much sense to use this technique for toolbar buttons, where buttons must be enabled/disabled based on the context.

TOOLBAR
   ...
   ITEM append
   ...
END

TOPMENU
   ...
   GROUP orders (TEXT="Orders")
     COMMAND sr_ord.append
   ...
END

LAYOUT
GRID
{
   ...
   [b002  ]
}
END
END

ATTRIBUTES
BUTTON b002: sr_ord.append;
END

If you bind an action view with a simple action name (without the sub-dialog prefix), the action view will be attached to any sub-dialog action with the matching name. This is especially useful for common actions such as the implicit insert / append / delete actions created by INPUT ARRAY, when the dialog handles multiple editable lists. Bind toolbar buttons to these actions without the sub-dialog prefix; the buttons will apply to the current list that has the focus. The action views bound to sub-dialog actions without the sub-dialog qualifier will automatically be enabled or disabled when entering or leaving the group of fields controlled by the sub-dialog (typical navigation buttons in the toolbar will be disabled if the focus is not in a list).

If a sub-dialog action is invoked when the focus is not in the sub-dialog of the action, the focus will automatically be given to the first field of the sub-dialog, before executing the user code defined in the ON ACTION clause. This will trigger the same validation rules and control blocks as if the user had selected the first field of the sub-dialog by hand.

When using DIALOG.setActionActive() (or any method that takes an action name as parameter), you can specify the action name with or without a sub-dialog identifier. If you qualify the action with the sub-dialog identifier, the sub-dialog action is clearly identified. If you don't specify a sub-dialog prefix, the action will be identified based on the focus context - when the focus is in the sub-dialog of the action, non-qualified action names identify the local sub-dialog action; otherwise, they identify a dialog action if one exists with the same name. Disabling an action by the program with setActionActive(), will take precedence over the built-in activation rules (this means that if the action is disabled by the program, the action will not be activated when entering the sub-dialog).

For action views bound to sub-dialog actions with qualifiers, the action defaults defined with the corresponding action name will be used to set the attributes with the default values. In other words, the prefix will be ignored. For example, if an action view is defined with the name "custlist.append", it will get the action defaults defined for the "append" action.