I am using a!gridField(). I want to allow the user to select only one row at a t

Please refer to following link from the SAIL recipe to limit the number of rows to be selected.

forum.appian.com/.../SAIL_Recipes.html

Another approach could be to show one Action column and provide links to view or select the row. Only one row can be selected at a time by using dynamic link.

Here is the SAIL recipe for more details.
forum.appian.com/.../SAIL_Recipes.html

The first example is using check boxes. Isn't there a way to simply display radio buttons? I checked all SAIL recipe and couldn't find any example with radio buttons.

Paging grid only supports checkboxes and not radio buttons but you can use editable grid for radio buttons. Add a!radioButtonField component to the a!gridRowLayout and it should display the radio button for the rows.

Please see the attached SAIL snippet for editable grid with radio buttons.

Editable grid with radio buttons.txt

Thank you very much!