How to add scroller for custom component in as 3? - actionscript-3

Question

I have a custom component with some properties. Now I want to add scroller for this component. I don't have any idea about it. I want to add this scroller in ActionScript file. Not in MXML file. Can anyone help me out from this?
Update:
<s:Scroller width="100%" height="100%">
<s:Group id="contentGroup" left="0" right="0" top="0" bottom="0" minWidth="0" minHeight="0">
<s:layout>
<s:VerticalLayout paddingTop="25" paddingLeft="25" paddingRight="15"/>
</s:layout>
</s:Group>
</s:Scroller>

Answer 1

I recommend adding the scroller in the MXML skin of your custom component.
Here's a tutorial on the scroller component from Adobe.

Answer 2

[Updated answer]
By setting the left="0" right="0" top="0" bottom="0" minWidth="0" properties for the contentGroup, you are always keeping that group the same size as the scroller. The direct effect is that you don't need scrollbars.
If you'd only want a vertical scroll bar you can add the left="0" right="0" properties the contentgroup width will never surpass the scroller but because the height grows based on the childeren it will generate a vertical scroll bar. You can do the same for bottom and top to create only a horizontal scrollbar.
If you want them both, remove any size indication properties. This way the contentGroups childelements will adjust the size and as soon as it gets larger then the scroller it will display scrollbars accordingly.
[Answer before question was changed]
If you are using a SkinnableComponentI agree with hidarikani.
But because you want to add the scroller in the actionscript, I'm guessing its not a SkinnableComponent.
The trick is that you need to add all the child elements inside a group inside the scroller.
var scroller:Scroller = new Scroller();
var content:Group = new Group();
scroller.addElement(content);
this.addElement(scroller);
#insert elements that need to be inside the scroller to the content group.
content.addElement(visualElement1);
content.addElement(visualElement2);
The content group can now resize based on his children and the scroller needs to be specified with a size so it can create scrollbars based on the size of the content group.