Force Numeric Entry in a Text Box Using API
This routine will cause a textbox control to accept only numeric input. Any other input (including the '-' and '.' keys) will be ignored. Note that it is still possible to paste non-numeric data into the textbox. There have been plenty of examples of this in the last couple of days - in the comments section of one of these someone suggested using the API. So, for anyone that is interested, this is one way of doing it... I've put this in the intermediate category only because it uses API functions - otherwise it's straightforward code. I've only tested this in VB6.0 on Win2k, but it should work on any Windows platform from Win95 up.
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Private Sub ForceNumeric(Box As TextBox) On Error GoTo Catch Dim nStyle As Long nStyle = GetWindowLong(Box.hWnd, GWL_STYLE) Call SetWindowLong(Box.hWnd, GWL_STYLE, nStyle Or ES_NUMBER) GoTo Finally Catch: Call MsgBox(Err.Description, vbCritical Or vbOKOnly, "Error") Finally: End Sub