>I know this can be done by Tools|Options. How can it be done programmatically? So that if there is no default button on the form, the enter key does not tab between controls.

In teh tools/options, if you hit help, you'll usually be shown what Check Box Correcponds to what Set command, is this the one you mean?

Enter or tab to exit fields

Specifies that you want to exit text boxes only by pressing ENTER or TAB. Otherwise, you can exit text boxes by typing past the last character in the text box. Corresponds to the SET CONFIRM command.