Unfortunately, RadioButtonList does not allow handling the click event for a separate item. Thus, it is better to use CheckBoxList to allow users to unselect items. Handle the SelectedIndexChanged event to emulate the RadioButtonList behavior in the following way:
[JScript]function OnCBLSelectedIndexChanged(s, e){ s.UnselectAll();if(e.isSelected) s.SetSelectedIndex(e.index);else s.UnselectIndices(e.index);}
Then, customize the control's images using the SpriteProperties property and specifying the corresponding theme name in the prefix of a CSS class:
[C#]settings.Properties.UncheckedImage.SpriteProperties.CssClass="dxEditors_edtRadioButtonUnchecked_DevEx";settings.Properties.CheckedImage.SpriteProperties.CssClass="dxEditors_edtRadioButtonChecked_DevEx";
See Also:
ASPxCheckBoxList - How to emulate ASPxRadioButtonList that allows users to unselect items