How do you add calendar control in dropdownlist using aspnet?

To add a calendar control in a dropdown list using ASP.NET, you can use a DropDownList control in combination with a Calendar control. First, create the DropDownList in your ASPX page and populate it with items. Then, add a Calendar control to the page and set its visibility to false by default. In the SelectedIndexChanged event of the DropDownList, check for a specific selection that should trigger the calendar to display, and set its visibility to true, allowing users to pick a date.