With TextBox1
If Not IsNumeric(.Value) Then GoTo ELine
If Sgn(Val(.Value)) = -1 Then GoTo ELine
Dt = InStr(1, .Value, ".")
If Dt > 0 Then
If Len(Mid(.Value, Dt)) > 4 Then GoTo ELine
End If
End With
Exit Sub
ELine:
With Application
.EnableEvents = False
TextBox1.Value = ""
.EnableEvents = True
End With
End Sub