Trying to implement a messagebox if data is not numeric

[TheJay]

I have code that checks for gaps and fills them in with sequential numeric data.

Sub AutoFill()
    Dim R&, F%
        R = ActiveCell.Row
    Do
        F = 1
        R = R + 1
        If IsEmpty(Cells(R, 1)) Then F = 0: Cells(R, 1) = Cells(R - 1, 1)
        If IsEmpty(Cells(R, 2)) Then F = 0: Cells(R, 2) = Cells(R - 1, 2) + 1
    Loop Until F
End Sub

I'm trying to introduce a message box if the user tries activating the code without the selection being numeric data and can't quite get my head around it. If not numeric data, show message and exit sub. If numeric data, continue to process without a message.

Sub AutoFill()
    Dim R&, F%
        R = ActiveCell.Row
    Do
        F = 1
        R = R + 1
        If Not IsNumeric Then
        MsgBox ("The selection is text, this keyboard shortcut will only work with numbers."), vbOKOnly + vbInformation, "Shortcut Information"
        Exit Sub
        End If
        Else
        If IsEmpty(Cells(R, 1)) Then F = 0: Cells(R, 1) = Cells(R - 1, 1)
        If IsEmpty(Cells(R, 2)) Then F = 0: Cells(R, 2) = Cells(R - 1, 2) + 1
        Loop Until F
End Sub

 

[Micron]

Without the data & code in a wb, hard to follow what you're saying. Seems that is, you got it to work but aren't sure why. That I can't answer since I have no idea what's in any R row. I still don't see how Do Until F can work reliably. Anyway, you've marked it as solved and seem to like how it functions so I guess that's all that matters.