You can use Victor's suggestion to use varchar instead of char (char pads the data with spaces on the right). If you do this, remember that you need to remove all the padding after you change the field definition.
Also setting MaxLength property of the Textbox fixes it in Winforms. See if that will fix it on Webforms.
>Sucker grows in WIDTH.
>
>Blow up is as follows:
>Cannot set column 'ap_fill1' to 'p8-123 '. The value violates the MaxLength limit of this column.