given:
public class Customer { public int Id { get; set; } public string FirstName { get; set; } public DateTime Birthdate { get; set; } }
Alternatively, you can update your front-end GridView display to hide out the DateTime.MinValue as follow:
<%# (DateTime)Eval("LastRequestDate").Equals(DateTime.MinValue) ? "" : string.Format("{0:dd/MM/yyyy hh:mm:ss tt}", (DateTime)Eval("LastRequestDate")) %>