Autofill cells based on drop down list in excel - excel

Question

I am trying to creata a VBA that gives me automatic values based on drop down list in a form. The problem is that when I run the macro then it is causing an error and excel stops working. Any help in this case is most welcome.
Private Sub Worksheet_Change(ByVal Target As Range)
If Range("$G$11") = "UD Sheet" Then
Rows("20:25").EntireRow.Hidden = False
Else
Rows("21:25").EntireRow.Hidden = True
End If
If Range("G12").Value = "Flex Tape" Then
Range("B20").Value = "None"
Else
Range("B20").Value = ""
End If
exitHandler:
Application.EnableEvents = True
Exit Sub
End Sub

Answer 1

First thing first, in your code, no need to put an Exit Sub before the End Sub.
The code will end after that line so this is a redundancy.
The next thing that you need to understand is that the Change Event will keep triggering if you will not disable it explicitly. So it means that when you hide a row on that Sheet, the Change Event will keep on happening since there will be changes that will happen on the Sheet. i.e. (Hiding Rows).
To do that you need to disable the EventsListeners of the application using the Application.EnableEvents = False. So the application can do a single thing based on that first event.
The next thing that you need to keep in mind is to track where the Changes occur and fire your program. Target is a Range Object that will return the Range where the specific change occurs on the Sheet.
In order to do that, you need to validate if you need to trigger the routine based on the target using the Intersect function.
The whole code is as follows:
Private Sub Worksheet_Change(ByVal Target As Range)
Application.EnableEvents = False
If Not Intersect(Target, Range("G11")) Is Nothing Then
If Range("$G$11") = "UD Sheet" Then
Rows("20:25").EntireRow.Hidden = False
Else
Rows("21:25").EntireRow.Hidden = True
End If
End If
If Not Intersect(Target, Range("G12")) Is Nothing Then
If Range("G12").Value = "Flex Tape" Then
Range("B20").Value = "None"
Else
Range("B20").Value = ""
End If
End If
Application.EnableEvents = True
End Sub