SAS/AF CheckList Class

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This class was created after reading and responding to a posting on SAS-L.

The class is used when you want to display a number of check boxes in the manner of a check list. Since there may be many check boxes, and only limited real-estate, the Check List class is implemented as a sub-class of the Work Area class. The Work Area class supports scrolling of components contained within it. The method setCheckListItems() is used deliver an SCL list of strings to the class. Each character item in the list becomes a check box; the check box label is the value of the item.

When a check box in the CheckList is clicked, the object label in the frame SCL will run (if it is defined). Use the object attribute lastCheckBoxClicked to obtain the object identifier of the check box that was clicked. Note: if an area of the CheckList is clicked, that does affect a check box, lastCheckBoxClicked will return a 0.

The list attribute checkBoxObjects is used to obtain an SCL list containing the object identifiers of the check boxes in the work area. Once the object identifier is known, developers can alter the display attributes of the check boxes (such as font and border) or query the .selection status.

Internal Design Notes

• Check List is a sub-class of Work Area
• A resource named 'Common.Components.CheckList_r.Resource' was created and a sashelp.classes.checkbox_c.class was added to it.
• The Check List Resource was set to 'Common.Components.CheckList_r.Resource'
• The Check List Scrollbars, Vertical and Horizontal are unchecked
• The Check List prevents the run-time Work Area Region Menu by setting Additional Attributes, Command Processing..., Popmenu Processing to 'Ignore It'
• The Check List prevents the run-time Work Area Item Menu by overridding method _childPopmenu with a do nothing method
• The Check List uses an undocumented sublist _attrs_ = { label = 'some label' } when adding newItem()
• The Check List disables drag and drop of each check box
• setCheckListItems() method sets a per-instance _onClick() method override for each check box created
• setCheckListItems() method adds a per-instance attribute 'wa_owner' to each check box. Used in the _onClick() override
• The Check List overrides _objectLabel() method

Undocumented feature of Work Area class _newItem() method

When new items are to be added to a work area programmatically, information about the components being added are passed to the _newItem method in an SCL list. The list has content as such:

items =
{ { <component-1> }
, ...
, { <component-N> }
};

The component sublist has content as such:

<component> = {
  _classname_ = "<alias as shown per resource entry named
                  in work area resource attribute>"
, _region_ = { ulx = <ulx>, uly = <uly>, lrx=<lrx>, lry = <lry> }
, _attrs_ = { <attribute-name> = <attribute-value> }	
};

The ability to specify an _attrs_ sublist is not documented (at least I have not found it). The attribute name value pairs appear to get merged with the component attributes that are set when the component is instantiated. Attribute name value pairs are foundational in the SAS component object model.

Future

Future work on this class could turn it into a viewer for models SclList and StaticStringList.
Enforcing or exposing certain object behaviours and attributes might require a rewrite using extended table or table editor as the parent class.