Error handling stopping after first loop through For Each loop - ms-access

Question

So I have already solved this problem, though I don't understand why my solution was required. I wanted to make a way to check properties on all forms and all controls within my database so I came up with the following code:
Public Function CheckPropertyAllForms()
Dim obj As Object
Dim ctl As Control
Dim blnFound As Boolean
For Each obj In CurrentProject.AllForms
DoCmd.OpenForm obj.Name, acDesign, , , , acHidden
blnFound = False
For Each ctl In Forms(obj.Name).Controls
On Error GoTo Next_Control
If Nz(ctl.ControlSource, "") <> "" Then
If ctl.ControlSource = "Certain_Field" Then
blnFound = True
End If
End If
Next_Control:
Next ctl
If blnFound = True Then
Debug.Print obj.Name
End If
DoCmd.Close acForm, obj.Name
Next obj
End Function
However this code would only work once, the second time around it would display the error as if error handling was turned off. So I updated it to this:
Public Function CheckPropertyAllForms()
Dim obj As Object
Dim ctl As Control
Dim blnFound As Boolean
For Each obj In CurrentProject.AllForms
DoCmd.OpenForm obj.Name, acDesign, , , , acHidden
blnFound = False
For Each ctl In Forms(obj.Name).Controls
On Error GoTo Err_Handler
If Nz(ctl.ControlSource, "") <> "" Then
If ctl.ControlSource = "Certain_Field" Then
blnFound = True
End If
End If
Next_Control:
Next ctl
If blnFound = True Then
Debug.Print obj.Name
End If
DoCmd.Close acForm, obj.Name
Next obj
Exit_Handler:
Exit Function
Err_Handler:
Resume Next_Control
End Function
Which works exactly how I want it to, however I couldn't find an answer online as to WHY this was happening with my first set of code. Could someone let me know what is happening with my first version of this function to cause the error handling to quit?
Edit: I should also point out that clearly the error handling will be needed because not all controls have a control source. Additionally I don't have a control type check because this function gets updated when a different property is going to be checked.

Answer 1

Along with your On Error statement, you need to have an On Error GoTo 0 statement, too. In your case, it would probably go right before your Next_Control and you could actually get rid of that so your loop would look like this:
For Each ctl In Forms(obj.Name).Controls
On Error Resume Next
If Nz(ctl.ControlSource, "") <> "" Then
If ctl.ControlSource = "Certain_Field" Then
blnFound = True
End If
End If
On Error GoTo 0
Next ctl
The reason for this is that in your first case, the error handler never clears the error object, and there can only be one error active at a time. When an error is active, and another error raises, the handler fails.