Select columns ranges in a VBA - excel

Question

I want to select a range (of values, the whole column) for the values: FirstDate, EndDate and Number. My VBA:
The Output of the below VBA is highlighted (Column D) :
Sub DateTest()
Dim FirstDate As Date ' Declare variables.
Dim IntervalType As String
Dim Number As Integer
Dim EndDate As Date
Dim TempDate As Date
Dim i As Integer
IntervalType = "m" ' "m" specifies MONTHS as interval.
FirstDate = Cells(1, 1).Value
EndDate = Cells(1, 2).Value
Number = Cells(1, 3).Value ' "Number" For the syntax DateAdd.
' If the number is not greater than zero an infinite loop will happen.
If Number <= 0 Then
MsgBox "Number needs to be greater than 0", vbCritical
Exit Sub
End If
i = 1
Do Until TempDate = EndDate
If i <= 1 Then
TempDate = DateAdd(IntervalType, Number, FirstDate)
Else
TempDate = DateAdd(IntervalType, Number, TempDate)
End If
i = i + 1
Debug.Print i
Loop
Range("D1").Value = i - 1
End Sub
As I wrote before I want to run my Macro not only for the first 3 cells (currently the macro works fine for the value (1,1) (1,2) (1,3)), as you can see above for FirstDate, EndDate and Number
I want to use for all dates in Column1, Column2, Column3 for example:
I already tried this:
Sub DateTest()
Dim FirstDate As Date ' Declare variables.
Dim IntervalType As String
Dim Number As Integer
Dim EndDate As Date
Dim TempDate As Date
Dim i As Integer
IntervalType = "m" ' "m" specifies MONTHS as interval.
With ActiveWorkbook.Worksheets(1)
lLastRow = .UsedRange.Rows.Count
For lRow = 1 To lLastRow
FirstDate = Format(.Cells(lRow, 1).Value, "YYYY-MM-DD")
EndDate = Format(.Cells(lRow, 2).Value, "YYYY-MM-DD")
Number = .Cells(lRow, 3).Value
' If the number is not greater than zero an infinite loop will happen.
If Number <= 0 Then
MsgBox "Number needs to be greater than 0", vbCritical
Exit Sub
End If
i = 1
Do Until TempDate = EndDate
If i <= 1 Then
TempDate = DateAdd(IntervalType, Number, FirstDate)
Else
TempDate = DateAdd(IntervalType, Number, TempDate)
End If
i = i + 1
Debug.Print i
Loop
Range("D1").Value = i - 1
Next
End With
End Sub
But is still transforming the 1 row.

Answer 1

If I'm understanding what you need correctly it's because you're calling out Range("D1").Value so it will always update that cell. You can make it more dynamic by using the lRow variable you already set up to place it into the correct row.
Replacing this Range("D1").Value = i - 1 with this Cells(lRow, 4).Value = i - 1
Sub DateTest()
Dim FirstDate As Date ' Declare variables.
Dim IntervalType As String
Dim Number As Integer
Dim EndDate As Date
Dim TempDate As Date
Dim i As Integer
IntervalType = "m" ' "m" specifies MONTHS as interval.
With ActiveWorkbook.Worksheets(1)
lLastRow = .UsedRange.Rows.Count
For lRow = 1 To lLastRow
FirstDate = Format(.Cells(lRow, 1).Value, "YYYY-MM-DD")
EndDate = Format(.Cells(lRow, 2).Value, "YYYY-MM-DD")
Number = .Cells(lRow, 3).Value
' If the number is not greater than zero an infinite loop will happen.
If Number <= 0 Then
MsgBox "Number needs to be greater than 0", vbCritical
Exit Sub
End If
i = 1
Do Until TempDate = EndDate
If i <= 1 Then
TempDate = DateAdd(IntervalType, Number, FirstDate)
Else
TempDate = DateAdd(IntervalType, Number, TempDate)
End If
i = i + 1
Debug.Print i
Loop
Cells(lRow, 4).Value = i - 1
'Range("D1").Value = i - 1
Next
End With
End Sub