Toggle button in Office 2019 ribbon

Question

I am trying to get a toggle button in the Word 2019 ribbon.

I have viewed many examples here on Stack Overflow, but I did not get it running.

My XML looks like:

<customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui" onLoad="loadRibbon">
    <ribbon>
        <tabs>
            <tab id="doc_management" label="Publishing" insertBeforeQ="TabDeveloper">
                <group id="doc_drafting" label="Drafting" autoScale="true">
                    <toggleButton id="toggling" label="Insert Watermark" imageMso="WatermarkGallery" onAction="togglingWatermark" getPressed="buttonPressed"/>
                </group>
            </tab>
        </tabs>
    </ribbon>
</customUI>

The corresponding VBA code:

Option Explicit
Public myRibbon As IRibbonUI
Public isPressed As Boolean
    
Sub loadRibbon(ribbon As IRibbonUI)
    
    Set myRibbon = ribbon
    
End Sub
    
Sub togglingWatermark(control As IRibbonControl, pressed As Boolean)
    
    Select Case control.ID
        isPressed = pressed
        Case "toggling"
            If isPressed Then
                MsgBox isPressed
            Else
                MsgBox isPressed
            End If
    End Select
    
    myRibbon.InvalidateControl control.ID
    
End Sub

Sub buttonPressed(control As IRibbonControl, ByRef returnedVal)
    
    Select Case control.ID
        Case "toggling"
            returnedVal = isPressed
    End Select
    
End Sub

The custom tab with corresponding button is present. I can also toggle the button. But I would expect to see a popup screen as soon as I toggle. And that is not happening. What am I missing? Any help would be very much appreciated!

EDIT:

It seems an instance of the IRibbonUI is not loaded. So it doesn't allow me to invalidate or use the callbacks in the first place. I verified this by adding MsgBox("Loaded") in the loadRibbon Sub. In my understanding, a message box should appear as soon as a Word document is opened.

The VBA code is saved in a macro-enabled Word template and stored in %appData%\Microsoft\Word\STARTUP. Adding a normal button that calls a Sub from the same template is working.

Eugene Astafiev Eugene Astafiev · Accepted Answer · 2020-05-20T20:51:09

The getPressed callback is invoked when Office invalidates the Fluent UI controls and enables you to specify whether the toggle button control is pressed. To get the callback invoked you need to use the IRibbonUI.InvalidateControl method which invalidates the cached value for a single control on the Ribbon user interface.

You can customize the Ribbon UI by using callback procedures in COM add-ins. For each of the callbacks that the add-in implements, the responses are cached. For example, if an add-in writer implements the getImage callback procedure for a button, the function is called once, the image loads, and then if the image needs to be updated, the cached image is used instead of recalling the procedure. This process remains in place for the control until the add-in signals that the cached values are invalid by using the InvalidateControl method, at which time, the callback procedure is again called and the return response is cached.

Moreover, the signature of the getPressed callbacks look like this:

Function GetPressed(control As IRibbonControl) As Boolean

It returns a boolean value indicating the pressed state. It is not an event handler like the onAction one.

Toggle button in Office 2019 ribbon

2 Answers