How to turn on 'Snap To Grid' on Excel start up with an add-in - vba

Question

I am looking for a way to automatically turn on Snap to Grid every time I start Excel.
I worked out this code and put it in an Add-In (.xlam) that I always load on Excel start-up.
Private Sub Workbook_Open()
Dim cbc As CommandBarControl
Set cbc = Application.CommandBars.FindControl(ID:=549)
If Not cbc.Enabled Then cbc.Execute
End Sub
But when I start Excel, it throws this error at cbc.Execute:
Can anyone tell me what is wrong?

Answer 1

I think you have two problems:
Problem 1
I believe that what you are trying to do with the Enabled property is to check the toggle state of the control. Instead, I think you want the State property instead (which doesn't show in intellisense). Your code should be something like this:
Public Sub ActivateSnapToGrid()
Dim cbc As CommandBarControl
Set cbc = Application.CommandBars.FindControl(ID:=549)
If Not cbc Is Nothing Then
If cbc.Enabled Then
'if snap to grid is off...
If cbc.State = 0 Then
cbc.Execute
'State should now = -1
End If
End If
End If
End Sub
Problem 2
The 'Snap to grid' control is not enabled if there is no workbook present (check this by closing all workbooks). In its current state, your code tries to execute in this case i.e. If Not cbc.Enabled Then cbc.Execute because I think you are trying to check if it is 'on' not if it is enabled.
Because an Excel add-in will load as a 'hidden' workbook, I don't believe it would enable the 'Snap to Grid' command bar control. Therefore, in the Workbook_Open event of the add-in then the control will be disabled and that's why you get the error.
You need an application-level event handler in your add-in. This is very common for Excel add-ins. See here on MSDN for some explanation. Plus also see this article by Chip Pearson which is very useful. It will allow you to write an event for any Workbook_Open event generated after your add-in loads.
So you will end up with this code (per Chip Pearson) in your add-in to call the sub I presented above (in Problem 1 section):
Private WithEvents App As Application
Private Sub Workbook_Open()
Set App = Application
End Sub
Private Sub App_NewWorkbook(ByVal Wb As Workbook)
Debug.Print "New Workbook: " & Wb.Name
Call ActivateSnapToGrid
End Sub
I haven't tested this thoroughly as it can't be known how your wrote your add-in. However, this is a very (if not the) standard pattern for doing this kind of stuff. See MSDN and the Chip Pearson article and you will figure out which code goes in a Class, in a Module etc.