Whinging Pom

This is not an obvious fact and this is not mentioned anywhere in the documentation: to bind to the member of the parent class both (child & parent classes) should be declared as [Bindable].

Here is the example:

public function Parent()
{
}
}

If you don’t specifically tell to compiler that class Parent is bindable, compiler will give you the infamous warning on the attempt to bind to any public member of the Parent class:

Data binding will not be able to detect assignments to "m_sText".

P.S. It is logical if you think about the meaning of the [Bindable] directive and and you know the fact that PropertyChange events is not fired for changes happened inside of the complex members.

AS3 has a mechanism for defining setters & getters for the member variables (pardon, properties).

Recently, I’ve bumped into the the strange thing: if you change directly the value:

this won’t generate propertyChangeEvent and all you bound variables won’t be notified about the change. So, instead when you need to notify others about the change, you have to do this:

This will cause the setter to be executed and propertyChangeEvent will be dispatched.

Using Ctrl or Shift keys in multiple items selection is a common thing. Unfortunately, it is appeared that it is common only among the advanced users. So, I decided to simplify the interface: simulate Ctrl key, so user will use single mouse click to select/unselect items in the DataGrid.

package

{

    import mx.controls.DataGrid;

    import mx.controls.listClasses.IListItemRenderer;



    public class EasySelectionDataGrid extends DataGrid

    {

        //this flag simulates holding a Ctrl key

        private var _holdCtrl:Boolean = false;



        public function EasySelectionDataGrid()

        {

            super();

        }



        public function set holdCtrl(value:Boolean):void

        {

            _holdCtrl = value;

        }



        public function get holdCtrl():Boolean

        {

            return _holdCtrl;

        }



        override protected function selectItem(item:IListItemRenderer, 

                              shiftKey:Boolean, 

                              ctrlKey:Boolean, 

                              transition:Boolean=true):Boolean

        {

            //override values if necessary

            return super.selectItem(item, shiftKey, 

                              _holdCtrl ? true: ctrlKey, 

                              transition);

        }

    }

}

If you want to bind in MXML to some static variable compiler will warn you that data changes to the value will be unnoticed with the following warning:

Data binding will not be able to detect assignments to "SOME_STATIC_VARIABLE".

I don’t like compiler errors and don’t like compiler warnings as well. So, to avoid this warning you can do the following:

Instead of:

you can do this:

Voilà!