Question : Data validation

How can I restrict a form textbox from accepting spaces in a string that is composed of letters and number. What I need is a validation to not accept spaces at the beginning end and in between the string been type in this textbox. Also I need the special character “^” to be allow.
 What will it be the best way to implement this validation, on the KeyDown/Press or change of the textbox event?

Thanks in advance for the help.

Answer : Data validation

you can try this one too, this will only allow aplhanumeric and the "^"

Private Sub txtBOXNAme_KeyPress(KeyAscii As Integer)
Select Case KeyAscii
    Case 32 To 47, 58 To 64, 91 To 93, 95 To 96, 123 To 126
        KeyAscii = 0
    Case Else
End Select

End Sub