This is one of several ways of stopping a user enter letters into a text box. It sets the window style for the text box, stopping it from accepting letters. This could also box done in the KeyPress event of the text box, just intercepting letters, but this way does not need code in the events of the text box.

Declarations

Declare Function GetWindowLong Lib "user32" _
Alias "GetWindowLongA" _
(ByVal hwnd As Long, ByVal nIndex As Long) As Long

Declare Function SetWindowLong Lib "user32" Alias _
"SetWindowLongA" _
(ByVal hwnd As Long, ByVal nIndex As Long, _
ByVal dwNewLong As Long) As Long

Functions

Public Const GWL_STYLE = (-16)
Public Const ES_NUMBER = &H2000&

Public Sub SetNumber(NumberText As TextBox, Flag As Boolean)
Dim curstyle As Long
Dim newstyle As Long

curstyle = GetWindowLong(NumberText.hwnd, GWL_STYLE)

If Flag Then
   curstyle = curstyle Or ES_NUMBER
Else
   curstyle = curstyle And (Not ES_NUMBER)
End If

newstyle = SetWindowLong(NumberText.hwnd, GWL_STYLE, curstyle)
NumberText.Refresh
End Sub