write-cell-value

Generic Function

Package: common-graphics

Arguments: grid-row grid-column value

This generic function may be called to write a value that the user has interactively entered into the grid cell defined by the row and column arguments back into an application's master data. Typically it is called by a cell-click method or a cell-key-down method that has interpreted a new cell value from the end user's mouse or keyboard gesture. If the grid column uses one of the built-in grid-column classes such as editable-text-column-mixin, then the cell-click or cell-key-down method that is supplied with the built-in column class will call write-cell-value internally. Otherwise an application may supply custom cell-click or cell-key-down methods that call write-cell-value. The default write-cell-value method (shown below) assumes that the common grid paradigm is being used where each grid row represents a data object (such as an employee) and each grid column represents an attribute of those objects (such as an employee's department).

;; default write-cell-value method
(defmethod write-cell-value ((row grid-row)(column grid-column) value)
  (let ((data-object (data-object row)))
    (and data-object
         (funcall (fdefinition (data-writer column))
                  value data-object))))

The default method may be used for cells that fit this paradigm if the application has therefore supplied data-object methods for the grid rows and data-reader methods for the grid columns. For grids that do not fit the object-rows-and-attribute-columns paradigm, the application could either supply a write-cell-value method that writes grid data to the application in a custom way, or else not use write-cell-value at all in its cell-click and cell-key-down methods.

See also read-cell-value and the description of the grid-widget.

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Created 2000.10.5.