It's the same magic Web Form programmers see with View State. Typically when I’m working with Drop Down Lists on my web pages, I like to add a “Select…” option to the list to prompt the user for a value.

A good way of using the Initial Value property is with the Drop Down List server control.a drop-down list might have a default value that is not an empty value (by default, some text appears in it).If you were to drop a simple Required Field Validator and target the drop down list, it would evaluate as Valid every time you submitted, since it treats –1 as a legitimate value. This works, however it does perform validation on some of the conditional elements on my page that are hidden.So lets attach a basic Required Field Validator control to this Drop Down List since we want to make sure a value has been specified: This validator displays an * next to the control itself and the error message is getting piped over to a Validator Summary control (not shown).The problem with this configuration is that by default, the Selected Index is set to 0 for the Drop Down List when it is databound.This is a community of tens of thousands of software programmers and website developers including Wrox book authors and readers. By joining today you can post your own programming questions, respond to other developers questions, and eliminate the ads that are displayed to guests. But if the user does not change the DOB THEN clicks the 'CONFIRM' button, it passes to the next page without re-checking the DOB drop-downs. Basically, it is validation to check for the date of births for a child.