Excel VBA add value to entire column that matches a specific header - excel

Question

So i need to add 2021 to the Assessment year column in my worksheet but the range keeps breaking
LastRow is returning the correct value but i cant manage to figure out why range isnt working
Sub AutoFill()
Dim rFind As Range
Dim ColumnLetter As Variant
Dim ColumnNumber As Variant
Dim LastRow As Variant
Dim Fill As Range
With Range("A1:P1")
Set rFind = .Find(What:="AssessmentYear", LookAt:=xlWhole, MatchCase:=False, SearchFormat:=False)
If Not rFind Is Nothing Then
ColumnNumber = rFind.Column
ColumnLetter = Split(Cells(1, ColumnNumber).Address, "$")(1)
LastRow = Cells(Rows.Count, 1).End(xlUp).Row
MsgBox ColumnLetter
MsgBox LastRow
Cells(LastRow, ColumnNumber).Value = "Here"
Range("ColumnLetter & 2 : ColumnLetter & LastRow").Value = "2021"
End If
End With
End Sub
I keep getting a method global failed error

Answer 1

The issue is VBA sees "ColumnLetter & 2 : ColumnLetter & LastRow" as a string and is not actually using the variables ColumnLetter or LastRow. Just change it to the below and it should work fine.
Range(ColumnLetter & "2 : " & ColumnLetter & LastRow).Value = "2021"

Answer 2

Auto Fill Data Column
Option Explicit
Sub AutoFillDataColumn()
Const hAddress As String = "A1:P1"
Const hTitle As String = "AssessmentYear"
Const cValue As Variant = 2021
Dim ws As Worksheet: Set ws = ActiveSheet
Dim hrg As Range: Set hrg = ws.Range(hAddress)
Dim rg As Range: Set rg = RefDataColumnByHeader(hrg, hTitle)
If rg Is Nothing Then Exit Sub
rg.Value = cValue
End Sub
Function RefDataColumnByHeader( _
ByVal HeaderRange As Range, _
ByVal HeaderTitle As String) _
As Range
If HeaderRange Is Nothing Then Exit Function
Dim hCell As Range
With HeaderRange
Set hCell = .Find(HeaderTitle, .Cells(.Rows.Count, .Columns.Count), _
xlFormulas, xlWhole, xlByRows)
If hCell Is Nothing Then Exit Function
If hCell.Row = .Worksheet.Rows.Count Then Exit Function
Debug.Print "Header Cell Address: " & hCell.Address(0, 0)
End With
Dim hrrg As Range
Set hrrg = Intersect(HeaderRange, hCell.EntireRow)
Debug.Print "Header Row Range Address: " & hrrg.Address(0, 0)
With hrrg
Dim lcrg As Range
Set lcrg = .Resize(.Worksheet.Rows.Count - .Row).Offset(1)
Debug.Print "Last Cell Range Address: " & lcrg.Address(0, 0)
Dim lCell As Range
Set lCell = lcrg.Find("*", , xlFormulas, , xlByRows, xlPrevious)
If lCell Is Nothing Then Exit Function
Debug.Print "Last Cell Address: " & lCell.Address(0, 0)
Set RefDataColumnByHeader = hCell.Resize(lCell.Row - .Row).Offset(1)
Debug.Print "Data Column Address: " _
& RefDataColumnByHeader.Address(0, 0)
End With
End Function