How to add a RequiredFieldValidator to DropDownList control?

Question

I have a DropDownList binded with aSqlDataSource to display the values from the database.

I am unable to validate using a RequiredFie

Answer 1

If you are using a data source, here's another way to do it without code behind.

Note the following key points:

• The ListItem of Value="0" is on the source page, not added in code
• The ListItem in the source will be overwritten if you don't include AppendDataBoundItems="true" in the DropDownList
• InitialValue="0" tells the validator that this is the value that should fire that validator (as pointed out in other answers)

Example: