DlangUI EditLine question

[Kyle via Digitalmars-d-learn]

I have a variable, x, which I want to update when the content of 
a DlangUI EditLine is modified. I tried making this work with the 
"onContentChange" method listed in the API documentation, but dmd 
told me it's not there. I've got this working now by implementing 
a custom subclass of EditLine as below:

class XEditLine : EditLine
{
    this(string ID, dstring initialContent = null)
    {
        super(ID, initialContent);
    }

    override bool onKeyEvent(KeyEvent e)
    {
        super.onKeyEvent(e);
        x = to!double(this.text);
        return true;
    }
}


This works but it seems like there should be a cleaner way to do 
this, any suggestions? Thanks.