VBA get parameters from IRibbonUI - vba

Question

So I have a custom ribbon that looks something like
<customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui" onLoad="RibbonLoadFunc" >
and a function
Private Sub RibbonLoadFunc(Ribbon As IRibbonUI)
MsgBox "Hello World"
End Sub
So when I open the document, it prints "Hello World" on the screen as expected. Now, my question is since a reference to IRibbonUI is passed into the function, can I get values of fields of underlying elements? Since the ribbon is defined as an XML document, I would imagine I should be able to access all elements within said document. So, for instance, if I also had
<tab id="myTab">
<group id="myGroup">
<button id="myButton" onAction="someAction" label="someLabel"/>
</group>
</tab>
Is there a way to print the label of myButton, "someLabel", instead of "Hello World"?
Alternatively, is there a way to pass constants into the onLoad function of a IRibbonUI?

Answer 1

This question borders on being too broad and you'd really need to do some extensive research on working with Ribbon XML. Microsoft has done a pretty good job of hiding its documentation since the release of the new JS APIs, so I compiled a list of links and posted it in the MSDN forums: https://social.msdn.microsoft.com/Forums/office/en-US/ba8c9d0b-7312-4503-8167-f2ef86f17435/information-on-the-office-fluent-ui-ribbon-for-developers?forum=officegeneral. I recommend you start with the 3-part series on "Customizing the Office 2007 Fluent UI for developers".
In a nutshell, though, the Ribbon UI interacts with code via "callbacks" - all interaction must be started by the Ribbon, itself. There's no way to "query" the Ribbon object and its controls as you're accustomed to doing using VBA. The VSTO extensions do provide this, as long as the Ribbon you want only requires things supported by its Ribbon Designer. But in the background that works more or less the way I describe below.
Your RibbonLoadFunc is such a callback. It's usually used to assign the Ribbon to a "global" RibbonUI object in your VBA module. Using that, you can at any time trigger the Invalidate or InvalidateControl methods.
At the same time RibbonLoadFunc is triggered when the Ribbon is loaded, the "get" attributes of other controls are triggered. These are used to dynamically populate things like labels and images. If you want to change these dynamic settings at some point, that's when Invalidate or InvalidateControl come into play - they force the "get" callbacks to run.
You can also use these "get" callbacks to populate additional global objects with information about the controls, so that you can use that information "outside" the Ribbon environment.
And that's basically the answer to your question: You can't use the RibbonLoadFunc to access and display information about other Ribbon controls. But the same "loading" that triggers RibbonLoadFunc can also provide information on any controls that have the corresponding "get" callbacks for what you want to "know".
For example, if you had the getLabel="SubInVBA" attribute in the XML for the button, that can dynamically assign the label to the button and at the same time store that information in a global variable and display it (any time you want, from the variable) in a MsgBox.