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'Controls - How to check whether given string is numeric or not without using IsNumeric function.
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0 ' What if it isn't a currency field?
' What if I don't want to support scientific notation?

'To cope with this issue, I have prepared an alternative function, which you can
'modify for your particular purposes. (For instance, you can add support for a
'currency symbol or the comma as the decimal separator.) Note that this function
'always returns True when it's passed a null string, so you might need to
'perform additional tests if the user isn't allowed to leave the field blank:

Function CheckNumeric(Text As String, DecValue As Boolean) As Boolean
    Dim I As Integer
    For I = 1 To Len(Text)
        Select Case Mid$(Text, I, 1)
        Case "0" To "9"
        Case "-", "+"
            ' Minus/plus signs are only allowed as leading chars.
            If I > 1 Then Exit Function
        Case "."
            ' Exit if decimal values not allowed.
            If Not DecValue Then Exit Function
            ' Only one decimal separator is allowed.
            If InStr(Text, ".") < I Then Exit Function
        Case Else
            ' Reject all other characters.
            Exit Function
        End Select
    Next
    CheckNumeric = True
End Function