Text box validation problems

Hi John,

I went old school and drew a flow chart of how I think your textbox validation function works, like I was taught when I was a wee young boy (see attached pdf and see if you agree). From further reading it appears functions don't always have to return values. I'm ashamed to say that I never considered using the AfterUpdate event . I used Exit events but had problems. This is the best solution I've come across for textbox validation. I never thought of Mid/InStr/While combination. This will help me with my hydrology project at work.

Paxton

Private Sub TextBox_r_AfterUpdate()
    Dim txtValue As Variant
    If Val(Me.TextBox_r.Value) < 0 Or Val(Me.TextBox_r.Value) > 1 Then
        MsgBox Me.TextBox_r.Name & " Value must be > 0 and less < 1"
        Me.TextBox_r.Value = ""
        Me.TextBox_r.SetFocus
        Exit Sub
    End If
    txtValue = Me.TextBox_r.Value
    Call NumberVal(txtValue)
    If Numeric = False Then
        Me.TextBox_r.Value = ""
        Me.TextBox_r.SetFocus
        Exit Sub
    Else
    End If
End Sub

Public txtValue As Variant
Public Numeric As Boolean
Option Explicit
Function NumberVal(txtValue) As Boolean
    Dim LPos As Integer
    Dim LChar As String
    Dim LValid_Values As String
    LPos = 1
    LValid_Values = " .0123456789"
    While LPos <= Len(txtValue)
        LChar = Mid(txtValue, LPos, 1)
        If InStr(LValid_Values, LChar) = 0 Then
            Numeric = False
            Exit Function
        End If
        LPos = LPos + 1
    Wend
    Numeric = True
End Function