How to unselect a dropdown in the Ribbon

[tvanstiphout]

NW2 Dev Edition has a ribbon with a dropdown showing MRU items. I'm re-using that concept in my own app.
When you drop it down and select the same item as is already selected, the Change event does not happen; no event happens whatsoever.
If it was a textbox, you could Invalidate the control and set it to "", so the same value can be entered again, but no such luck with a dropdown.
I tried returning Null or -1 or nothing at all from the GetSelectedItemIndex callback, but the first two result in errors, the third does not help (first item is selected).
Is there indeed no way to re-select the same item and respond to that action? Not even a slimy hack?

 

[isladogs]

I've never had a reason to do this but how about first clearing the existing entry on before update?

 

[tvanstiphout]

Sorry Colin, the Ribbon is its own thing with its own object model. There is no BeforeUpdate event.
Ribbons for Access 2007 / Access 2010 – DropDown (accessribbon.de)

 

[isladogs]

Oops. That falls into the category of the last sentence in my signature line.

So I asked CoPilot which told me:

Clearing a dropdown in the ribbon using VBA can be achieved through different approaches. Let’s explore a couple of methods:

1. Using Callbacks in Custom Ribbon XML:
   • If you have a custom ribbon with a dropdown, you can add a callback to clear the selected item. Here’s an example:
     ' Add the following callback in your VBA code:
     Sub CallbackDDGetSelectedItemID(control As IRibbonControl, ByRef itemID)
     ' Callback to get the selected item for the dropdown control
     Select Case control.ID
     Case "myDropDown" ' Replace with your actual dropdown ID
     itemID = "" ' Clear the selected item
     End Select
     End Sub
     
     ' Then call this in the dropdown's OnAction event:
     objRibbon.InvalidateControl("myDropDown")
     
     
   • Replace "myDropDown" with the actual ID of your dropdown. This approach invalidates the control, effectively clearing the selection 1.
2. Direct Access to Ribbon Element Values:
   • If you want to access the dropdown element values directly, you can use callbacks like GetSelectedItemIndex, GetItemLabel, and GetItemID. For instance:
     Sub GetSelectedItemIndex(control As IRibbonControl, ByRef returnedVal)
     ' Returns the index position of the selected item from the dropdown control
     If control.ID = "Drop" Then
     MsgBox returnedVal
     End If
     End Sub
     
     Sub GetItemLabel(control As IRibbonControl, Index As Integer, ByRef returnedVal)
     ' Returns the label of the selected item from a ribbon dropdown control
     ' Implement similar logic for GetItemID
     ' ...
     End Sub
     
     
   • You can pass a control object from one callback to another, manually invoking these procedures 2.

Anything of use there? Or is that equally useless?

 

[tvanstiphout]

The first one looks plausible. I will try that. Thanks!

 

[tvanstiphout]

Plausible, but did not work. Returning Null or "" or -1 from GetSelectedItemID callback gives the same error as when using GetSelectedItemIndex: The callback "..." returned a value that could not be converted to the expected type.
or
The callback "..." returned an invalid value.
I'm thinking of a workaround of adding "--- Select a value ---" to the dropdown, and have it at Index=0.

 

[GPGeorge]

Plausible, but did not work. Returning Null or "" or -1 from GetSelectedItemID callback gives the same error as when using GetSelectedItemIndex: The callback "..." returned a value that could not be converted to the expected type.
or
The callback "..." returned an invalid value.
I'm thinking of a workaround of adding "--- Select a value ---" to the dropdown, and have it at Index=0.

I have used a method similar to that in Access combo boxes. But I tend to be lazy, so there's that to consider.