How do you get the namespace of a component? - actionscript-3

Question

I'm trying to write CSS stylesheet dynamically but Flex 4 requires that you declare the namespace in the Style markup.
If I have a Spark Button or MX Button class or class instance how would I get the namespace of that button?
So far I've tried this:
var className:Object = getQualifiedClassName(myButton);
var ButtonClass:Object = ApplicationDomain.currentDomain.getDefinition(className);
var button:Object = new ButtonClass();
With that information I can write this:
<fx:Style>
myButton {
color: red;
}
</fx:Style>
I need to create this:
<fx:Style>
#namespace s "library://ns.adobe.com/flex/spark";
#namespace mx "library://ns.adobe.com/flex/mx";
s|Button {
color: red;
}
</fx:Style>
I would like to be able to get this information at runtime but design time may be acceptable as well.

Answer 1

It's the same format as the namespace in the MXML code. I.e., if you have components in com.xyzzy.components, the MXML namespace is something like
xmlns:components="com.xyzzy.components.*"
And the CSS namespace would be like
#namespace components "com.xyzzy.components.*";
components|myButton {...}

Answer 2

It looks like I can't get it at runtime but I can get it XML files from the SDK directory and create a table of classes and their namespace.
In $FlashBuilder/sdks/4.6.0/frameworks/flex-config.xml there is a node called namespaces that contain the URI of the namespace and then a reference to the XML file that contains a list of classes in that namespace.
<!-- Specify a URI to associate with a manifest of components for use as MXML -->
<!-- elements. -->
<namespace>
<uri>http://ns.adobe.com/mxml/2009</uri>
<manifest>mxml-2009-manifest.xml</manifest>
</namespace>
<namespace>
<uri>library://ns.adobe.com/flex/spark</uri>
<manifest>spark-manifest.xml</manifest>
</namespace>
<namespace>
<uri>library://ns.adobe.com/flex/mx</uri>
<manifest>mx-manifest.xml</manifest>
</namespace>
<namespace>
<uri>http://www.adobe.com/2006/mxml</uri>
<manifest>mxml-manifest.xml</manifest>
</namespace>
<namespace>
<uri>http://flex.apache.org/ns</uri>
<manifest>apache-manifest.xml</manifest>
</namespace>
<namespace>
<uri>http://flex.apache.org/experimental/ns</uri>
<manifest>experimental-manifest.xml</manifest>
</namespace>
</namespaces>
I can use that information and the MXML document to add the necessary namespace to each node.