validateMenuItem:

Return Value 戻り値

YES to enable menuItem, NO to disable it.

Discussion 解説

The object implementing this method must be the target of menuItem. You can determine which menu item menuItem is by querying it for its tag or action.

The following example disables the menu item associated with the nextRecord action method when the selected line in a table view is the last one; conversely, it disables the menu item with priorRecord as its action method when the selected row is the first one in the table view. (The countryKeys array contains names that appear in the table view.)

- (BOOL)validateMenuItem:(NSMenuItem *)item {
    int row = [tableView selectedRow];
    if ([item action] == @selector(nextRecord) &&
        (row == [countryKeys indexOfObject:[countryKeys lastObject]])) {
        return NO;
    }
    if ([item action] == @selector(priorRecord) && row == 0) {
        return NO;
    }
    return YES;
}