Fill textbox with the value of a cell

[zvonacfirst]

Hello.
I have a code that have to fill a textbox with the value of last non empty cell from column F in active sheet.
This code doesn't work, the textbox in frmInregistrare remain empty.
The cause is because cells from column F isn't really empty, all cells have formulas.
I think I know which is the wrong line but I don't know how it have to be modified.
Could you help me, please?
I've attached an example.
Thanks.

The code that I have is follow:

Private Sub UserForm_Initialize()
   
    Dim ws As Worksheet
    Dim lstRw As Long
   
        Set ws = ActiveSheet
       
        With ws
        lstRw = .Rows.Count
        Me.txtDocNumber = .Range("F" & lstRw).End(xlUp).Value     ' This I think is the wrong line
        End With
       
End Sub

[AlphaFrog]

The .Find method can return the last used cell value excluding null strings (i.e. "")

Private Sub UserForm_Initialize()
    
    Me.txtDocNumber = Range("F:F").Find("*", , xlValues, , , xlPrevious).Value
    
End Sub

[MarvinP]

Perhaps something like this??

Private Sub UserForm_Initialize()
    
    Dim ws As Worksheet
    Dim lstRw As Long
    
        Set ws = ActiveSheet
        
        With ws
        lstRw = .Cells(.Rows.Count, "F").End(xlUp).Row
        Me.txtDocNumber = .Cells(lstRw, "F").Value
        End With
        
End Sub

[zvonacfirst]

Both of codes work perfectly.
Thank you @AlphaFrog and @MarvinP.

The following code also works fine.

Private Sub UserForm_Initialize()
    Dim ws As Worksheet
    Dim i As Long
    Set ws = ActiveSheet: i = 6
    Do
    i = i + 1: Loop While ws.Range("F" & i + 1) <> ""
    Me.txtDocNumber = ws.Range("F" & i)
    Set ws = Nothing
End Sub