Exit the main sub if a called sub calls `Exit Sub` - excel

Question

I have a sub that calls another sub and most often I need to exit the called sub and stop executing the rest of the sub that called it.
So I have the sub Add_Format_Button_Click that calls another sub:
call CheckEmptyComboboxValues
And most often CheckEmptyComboboxValues will end up on
Exit sub
But the Add_Format_Button_Click will continue executing the rest of it. This is where I need help because when CheckEmptyComboboxValues exits, I need the Add_Format_Button_Click to also exit.
Could someone help me solve this, seemingly simple problem?
EDIT: CheckEmptyComboboxValues contains tens if not hundreds of if statements that follow the structure of:
If Format_Layout.FilmType.Value = "" Then
MsgBox "Specify a film type!", , ("Film Type"): Exit sub
End If
So I guess I need to turn that exit sub value into something I can check in the main sub with an if statement like
if CheckEmptyComboboxValues .value = "Exit sub" Then
exit sub

Answer 1

3 solutions, each of them works for your case. I would go with the first or last solution. Depends a bit on the design of the rest of your project:
1. Function
Function CheckEmptyComboboxValues() As Boolean
If AnythingOddHappens Then
Exit Function
End If
CheckEmptyComboboxValues = True
End Function
The result of this function is only True if it runs through the end, whenever you exit it before it is False
Sub Example()
If Not CheckEmptyComboboxValues Then Exit Sub
'instead of
'Call CheckEmptyComboboxValues
End Sub
2. Procedure with cancel
Sub CheckEmptyComboboxValues(ByRef Cancel As Boolean)
If AnythingOddHappens Then
Cancel = True
Exit Sub
End If
End Sub
Sub Example()
Dim Cancel As Boolean
Call CheckEmptyComboboxValues(Cancel)
If Cancel Then Exit Sub
End Sub
This can be used, but here I see no advantage and would prefer the function above. This method can be useful if you already have a function with a return value and want an additional cancel or in case you write code for an event.
3. Throw an error
Sub CheckEmptyComboboxValues()
If AnythingOddHappens Then
Err.Raise vbObjectError + 513, "CheckEmptyComboboxValues", "Something odd happened"
Exit Sub
End If
End Sub
Sub Example()
On Error Goto ERR_HANDLER
Call CheckEmptyComboboxValues
Exit Sub
ERR_HANDLER:
MsgBox "check failed"
End Sub
This can be an advantage if you have multiple check procedures/functions that can throw errors. Compared with the first or second solution where you need to check the result of each single check procedure/function this solution needs only one error handler, and threfore comes with slim code.
This also has the advantage that the check procedure now can return different type of errors that your calling sub can use to provide further assistance to the user. While the first 2 solutions are more like "It didn't pass the check" the last solution can provide more detailed information like "It didn't pass the check because of A/B/C happened" depending on which error was raised.
Sub CheckEmptyComboboxValues()
If AnythingOddHappens Then
Err.Raise vbObjectError + 513, "CheckEmptyComboboxValues", "Something odd happened"
Exit Sub
End If
' more code here …
If AnythingDifferentOddHappens Then
Err.Raise vbObjectError + 514, "CheckEmptyComboboxValues", "Something different odd happened"
Exit Sub
End If
End Sub
Now you can use the different error numbers to provide a more detailde infomation to the user about what went wrong and not just something went wrong.
Sub Example()
On Error Goto ERR_HANDLER
Call CheckEmptyComboboxValues
Exit Sub
ERR_HANDLER: 'possibility to give a more detailed information
Select Case Err.Number
Case vbObjectError + 513
MsgBox "check A failed"
Case vbObjectError + 514
MsgBox "check B failed"
Case Else
MsgBox "Undefined fail"
End Select
End Sub

Answer 2

Rewrite CheckEmptyComboboxValues to a function which returns a boolean. In Add_Format_Button_Click you can then write
if CheckEmptyComboboxValues then
' You could give a message
Exit Sub
else
' rest of the code of
' Add_Format_Button_Click
end if
CheckEmptyComboboxValues might look like that
Function CheckEmptyComboboxValues as boolean
' code goes here
if .... then
CheckEmptyComboboxValues = False
exit function
else
' other code
end if
CheckEmptyComboboxValues = True
End Function
Update based on the edit
Function CheckEmptyComboboxValues() As Boolean
' ....
If Format_Layout.FilmType.Value = "" Then
MsgBox "Specify a film type!", , ("Film Type")
CheckEmptyComboboxValues = True
Exit Function
End If
' ....
CheckEmptyComboboxValues = False
End Function