Multilevel action conflicts

Actions can be defined at two levels in a singular dialog, and three levels in the context of a DIALOG block:

1. Dialog level
2. Sub-dialog level (procedural DIALOG only)
3. Field level (ON ACTION with INFIELD clause)

It is not good practice to use the same action name at different levels of a dialog: This makes action view bindings and action handling (i.e. enabling / disabling) very complex, because there are many possible combinations. Therefore, when using the same action name at different dialog levels, the fglcomp compiler will raise a warning -8409. However, it is legal to use the same action name for a given level of action handlers in a sub-dialogs or for field-actions. For example, using the "zoom" action name for multiple ON ACTION INFIELD handlers is a common practice.

When binding action views with full qualified names, the ON ACTION handler is clearly identified, and the corresponding user code will be executed. However, when you do not specify the complete prefix of a sub-dialog or field action, the runtime system searches for the best ON ACTION handler to be executed, according to the current focus context.

Take for example a DIALOG instruction defining three ON ACTION print handlers at the dialog, sub-dialog and field level:

DIALOG
  INPUT BY NAME ... ATTRIBUTES (NAME = "cust")
    ...
    ON ACTION print INFIELD cust_name -- field-level action (1)
      ...
    ON ACTION print                   -- sub-dialog-level action (2)
      ...
  END INPUT
  ...
  ON ACTION print                     -- dialog-level action (3)
    ...
END DIALOG

The action views of the form will behave as follows:

• Action views bound with the name "print" will always be active, and invoke the ON ACTION print handler corresponding to the current focus context:
  • (1) is invoked if the focus is in the cust_name field.
  • (2) is invoked if the focus is in the cust sub-dialog, but not in cust_name field.
  • (3) is invoked if the focus is in another sub-dialog as cust sub-dialog.
• Action views bound with the name "cust.print" will always be active, even if the focus is not the cust sub-dialog, and invoke the ON ACTION print handler according to the current focus context:
  • (1) is invoked if the focus is in the cust_name field.
  • (2) is invoked if the focus is in the cust sub-dialog, but not in cust_name field.
• Action views bound with the name "cust.cust_name.print" will always be active, and invoke the ON ACTION print INFIELD cust_name handler after giving the focus to the cust_name field.

If the first field of a sub-dialog defines an ON ACTION INFIELD with the same action name as a sub-dialog action, and the focus is not in that sub-dialog when the user selects an action view bound with the name sub-dialog-name.action-name, the runtime system gives the focus to the first field of the sub-dialog. This field becomes the current field, and the runtime system executes the field-specific action handler instead of the sub-dialog action handler.

To avoid mistakes and complex combinations, you should use specific action names for each dialog level.