Get row number of first empty cell in column and store that value in other cell - excel

Question

I want to find row number of first empty cell in column and store that row number in Cell Z1.
I tried with Following macro code but it goes into loop forever.
As soon as it tries to set the value in Cell Z1 it again goes into worksheet_change event again and then again in for loop.
Private Sub Worksheet_Change(ByVal Target As Range)
Dim ws As Worksheet
Set ws = ActiveSheet
For Each cell In ws.Columns(3).Cells
If IsEmpty(cell) = True Then Range("$Z$1").Value = cell.Row: Exit For
Next cell
End Sub
Please help to resolve this.
Thanks

Answer 1

Maybe this code is of any help
Option Explicit
Function firstEmptyCell(col As Long, Optional ws As Worksheet) As Range
If ws Is Nothing Then
Set ws = ActiveSheet
End If
Dim rg As Range
Set rg = ws.Cells(1, col)
If Len(rg.Value) = 0 Then
Set rg = rg.Offset
Else
If Len(rg.Offset(1).Value) = 0 Then
Set rg = rg.Offset(1)
Else
Set rg = rg.End(xlDown)
Set rg = rg.Offset(1)
End If
End If
Set firstEmptyCell = rg
End Function
And the Event code is
Private Sub Worksheet_Change(ByVal Target As Range)
On Error GoTo EH
If Target.Column <> 12 Then
Exit Sub
End If
Application.EnableEvents = False
Range("Z1").Value = firstEmptyCell(12).Row
EH:
Application.EnableEvents = True
End Sub
Update: Based on the comments regarding the pitfalls of the change event one could change firstEmptyCell slightly and use a UDF only
Function firstEmptyCellA(col As Long, Optional ws As Worksheet) As Long
On Error GoTo EH
If ws Is Nothing Then
Set ws = ActiveSheet
End If
Application.Volatile
Dim rg As Range
Set rg = ws.Cells(1, col)
If Len(rg.Value) = 0 Then
Set rg = rg.Offset
Else
If Len(rg.Offset(1).Value) = 0 Then
Set rg = rg.Offset(1)
Else
Set rg = rg.End(xlDown)
Set rg = rg.Offset(1)
End If
End If
firstEmptyCellA = rg.Row
Exit Function
EH:
firstEmptyCellA = 0
End Function

Answer 2

Tricky Enable Events
This is triggered only when a cell in the 12th column (L) is changed, otherwise there is no need for it. If you have formulas there, then this will not work and you'll have to use the Worksheet_Calculate event.
Row of First Empty Cell in Column
Option Explicit
' Row of First Empty Cell in Column
Private Sub Worksheet_Change(ByVal Target As Range)
Const TargetCell As String = "Z1"
Const TargetColumn As Variant = 12 ' (or "L")
Dim rng As Range
If Intersect(Columns(TargetColumn), Target) Is Nothing Then Exit Sub
Application.EnableEvents = False
Set rng = Columns(TargetColumn).Find(What:="", _
After:=Cells(Rows.Count, TargetColumn), LookIn:=xlValues)
If rng Is Nothing Then
Range(TargetCell).Value = 0 ' Full column. No empty cells.
Else
Range(TargetCell).Value = rng.Row
End If
Application.EnableEvents = True
End Sub
Row of First Empty Cell After Last Non-Empty Cell in Column
Option Explicit
' Row of First Empty Cell After Last Non-Empty Cell in Column
Private Sub Worksheet_Change(ByVal Target As Range)
Const TargetCell As String = "Z1"
Const TargetColumn As Variant = 12 ' (or "L")
Dim rng As Range
If Intersect(Columns(TargetColumn), Target) Is Nothing Then Exit Sub
Application.EnableEvents = False
Set rng = Columns(TargetColumn).Find(What:="*", LookIn:=xlFormulas, _
SearchDirection:=xlPrevious)
If rng Is Nothing Then ' Empty column. No non-empty cells.
Range(TargetCell).Value = 1
Else
If rng.Row = Rows.Count Then ' Last (bottom-most) cell is not empty.
Range(TargetCell).Value = 0
Else
Range(TargetCell) = rng.Offset(1).Row
End If
End If
Application.EnableEvents = True
End Sub

Answer 3

Dont need a loop. Paste this in a module not in a worksheet event unless you want it for every worksheet change.
Sub Macro1()
ActiveSheet.Range("Z1") = ActiveSheet.Columns(3).SpecialCells(xlCellTypeBlanks)(1).Row
End Sub
if you want it after every change then put it in a worksheet as. This code will not run everytime. It will check if Z1 is empty then enter the valu. Then if Z1 is not empty it will check if the target cell is in column C
Private Sub Worksheet_Change(ByVal Target As Range)
Dim Rng As Range
Set Rng = ActiveSheet.Columns(3)
If IsEmpty(Range("Z1")) Then
Range("Z1") = Rng.SpecialCells(xlCellTypeBlanks)(1).Row
Else
If Not Intersect(Range("C1:C" & Range("Z1").Value), Target) Is Nothing Then
Range("Z1") = Rng.SpecialCells(xlCellTypeBlanks)(1).Row
End If
End If
End Sub