menu-items-for-combo-box-range

Generic Function

Package: common-graphics

Arguments: range-object-list row column

This generic function is called when a grid combo-box cell (a cell in a combo-box-column-mixin column) is about to show its choices to the user as a pop-up menu that is displayed somewhat like a combo-box. The method returns a list of menu-items to display. The menu-values are a list of the actual choices for the cell, as returned by the column's range-reader function called on the row's data-object.

The default method creates menu-items with the print-name of each choice displayed in the menu. An application could add a method to this generic function to instead create menu-items that have some sort of alternative string displayed on the menu for each choice.

Here's an example of defining a custom menu-items-for-combo-box-range method for an application's own combo-box grid-column subclass. The method adds a sequential number (1 through N) to each of the choices that are displayed to the user.

(defclass my-combo-box-column 
          (combo-box-column-mixin grid-column)())

(defmethod menu-items-for-combo-box-range
    (range-object-list row (column my-combo-box-column))
  (declare (ignore row))
  (let* ((number 0))
    (mapcar #'(lambda (object)
                (make-instance 'menu-item
                  :value object
                  :title (format nil "~a ~a" (incf number) object)))
      range-object-list)))

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Created 2000.10.5.