Excel VBA For Loop Error - vba

Question

I'm trying to run a simple For loop which will be expanded to include more functionality later but having trouble as it keeps throwing an error "invalid next control variable reference". The code I am trying to use is listed below.
Sub Tickbox()
Set Location = Sheets("TickBoxSheet").Range("B:B")
i = WorksheetFunction.CountA(Location)
Sheets("TickBoxSheet").Range("B2").Select
For a = 1 To i
If Selection.Value = "True" Then
Row = Selection.Row
'Hide some rows in another sheet via if statements
ActiveCell.Offset(1, 0).Select
End If
Next i
End Sub
I don't know if I need more coffee this morning but I can't seem to figure out what the hell is going on. Any help will be greatly appreciated.

Answer 1

The incremented variable (in Next) should be the index variable, i.e.:
For a = 1 To i
'...
Next a
i is so popular as index that you should think twice before using it in other contexts.

Answer 2

You have already got your answer from llmo. However there are few other things I would like to stress upon...
Try and avoid .Select. It will slow down your code.
Also It is not necessary that WorksheetFunction.CountA(Location) will give you the last row considering that you want to loop through all the rows which have data. I suggest this
Sub Tickbox()
Dim i As Long, a As Long, Rw As Long
With Sheets("TickBoxSheet")
i = .Range("B" & .Rows.Count).End(xlUp).row
For a = 2 To i
If .Range("B" & a).Value = "True" Then
Rw = a
'Hide some rows in another sheet via if statements
End If
Next a
End With
End Sub
You can make it more fast using Autofilter as well so that you loop through cells which only have True For example
Sub Tickbox()
Dim i As Long, a As Long, Rw As Long
Dim Location As Range, acell As Range
With Sheets("TickBoxSheet")
'~~> Remove any filters
.AutoFilterMode = False
i = .Range("B" & .Rows.Count).End(xlUp).row
With .Range("B1:B" & i)
.AutoFilter Field:=1, Criteria1:="True"
Set Location = .Offset(1, 0).SpecialCells(xlCellTypeVisible).EntireRow
Debug.Print Location.Address
End With
'~~> Remove any filters
.AutoFilterMode = False
For Each acell In Location
If acell.Value = "TRUE" Then
Rw = acell.row
'Hide some rows in another sheet via if statements
End If
Next acell
End With
End Sub