You could do:
radio1.SelectedIndex = 1;
But this is the most simple form and would most likely become problematic as your UI grows. Say, for instance, if a team member inserts an item in the RadioButtonList
above option2
but doesn't know we use magic numbers in code-behind to select - now the app selects the wrong index!
Maybe you want to look into using FindControl in order to determine the ListItem
actually required, by name, and selecting appropriately. For instance:
//omitting possible null reference checks...
var wantedOption = radio1.FindControl("option2").Selected = true;