How to run a dialog's method from a button's event handler?

Question

I've created my first dialog from the samples, but I am having trouble figuring out how to run a method in my dialog from an button's event handler. Can anyone please point me in the right direction?
function CreateDialog() 
    this.windowRef = null;
CreateDialog.prototype.run = function()
    //...declare a bunch of vars
    // Create a window of type palette.
    var win = new Window("dialog", "Element Spray Generator",[iTop,iLeft,iTop + iWidth,iLeft + iHeight] );  // bounds = [left, top, right, bottom] 
    this.windowRef = win;
    // Add a frame for the contents.   
    win.btnPanel = win.add("panel", [iPadding,iPadding,iWidth-iPadding,iHeight-iPadding], "");
    .... add a bunch of other stuff ...
    win.btnAdd = win.btnPanel.add("button", [win.btnRemove.bounds.left - iPadding - iButtonWidth,win.lstImages.bounds.bottom + iSmPadding,win.btnRemove.bounds.left - iPadding,win.lstImages.bounds.bottom + iSmPadding +iTextHeight], "Add");
    win.btnAdd.onClick = function() {
       //todo implement this
       var f = File.openDialog("Open File") ;
       win.lstImages.add("item", f.displayName );
       this.EnableControls();    //<--- problem is on this line here!!
    this.EnableControls();  //<--- this works
    // Display the window
    win.show();
    return true;      
CreateDialog.prototype.EnableControls = function (){
    var result = true;
    result = result && (this.windowRef.ddlPaths.selection != "");
    result = result && (this.windowRef.lstImages.items.length > 0);
    this.windowRef.btnOK.enabled = result;

Answer 1

This may not be the reason, but when using the way I create dialogs 'this' inside of an onClick points to the control.
    win.btnAdd.onClick = function() {
       //todo implement this
       var f = File.openDialog("Open File") ;
       win.lstImages.add("item", f.displayName );
       this.EnableControls();    //<--- I would expect it to call another function of btnAdd
                                        // this.parent.EnableControls() might be what you want if the control is not in some other container