Order of radio button options and default option

1. Do radio buttons need to be selected by default?
2. What is the default event for radio button control?
3. Can radio button have more than 2 options?
4. Should radio buttons be stacked?

Do radio buttons need to be selected by default?

Always Offer a Default Selection

One of the 10 heuristics of UI design says that users should be able to undo (and redo) their actions. This means enabling people to set a UI control back to its original state. In case of radio buttons this means that radio buttons should always have exactly one option pre-selected.

What is the default event for radio button control?

The CheckedChanged event is raised when the value of the Checked property changes. If the AutoCheck property is set to true (the default), when the radio button is selected all others in the group are automatically cleared.

Can radio button have more than 2 options?

Radio buttons allow a user to select a single option among multiple options. You can set the Choice Value of each option, for each button, as well as group these buttons by giving them the same Group Name.

Should radio buttons be stacked?

Based on research from the Neilson Norman Group as well as the various human interface guidelines for Apple and Microsoft, radio buttons should have the circle to the left of the label, and the list should be stacked vertically.