Accessing the DropDownList Control's SelectedIndex or SelectedValue Properties Selects the First ListItem

I was recently helping a colleague squash a bug that had popped up on a page that involved a DropDownList. Specifically, an HttpException was being thrown with the error message Cannot have multiple items selected in a DropDownList. This exception is raised, as the message notes, if a DropDownList contains multiple ListItems whose Selected properties are set to true.

The page in question had a DropDownList whose ...Full Article.