title: Data anntotation attributes. How to set order of execution?
body: <p>I created validation attributes for the date of birth like this:</p>
  
  <pre><code>public class DateRequired : ValidationAttribute
      {
          public override bool IsValid(object value)
          {
              DateTime date = Convert.ToDateTime(value);
              return date != DateTime.MinValue;
          }
      }
  
      public class DateGraterThanEighteen : ValidationAttribute
      {
          public override bool IsValid(object value)
          {
              DateTime date = Convert.ToDateTime(value);
              long ticks = DateTime.Now.Ticks - date.Ticks;
              int years = new DateTime(ticks).Year;
              return years &gt;= 18;
          }
      }
  
  I applied attributes like this
  
          [DateGraterThanEighteen(ErrorMessage="You must be at least 18")]
          [DateRequired(ErrorMessage = "Date of birth is required")]
          public DateTime DateOfBirth { get; set; }
  </code></pre>
  
  <p>No matter the order i apply them, DateGraterThanEighteen executes first. How can i make DateRequired to execute first?</p>