title: asp.net custom validator question
body: <p>I am familiar with how to write and use custom validators for the simple cases (i.e. making sure that a date is greater than or equal to some value).</p>
  
  <p>How would you approach this type of (common) scenario:</p>
  
  <p>I have a drop-down list with 5 choices, depending on which choice is selected, several other fields need to be validated. For example, if choice "3" is made from the drop down, I need to make sure fields a,b,c are filled in, but if choice "2" is made from the drop down I need to make sure a,b are blank and e,f are filled in etc.</p>
  
  <p>I guess the question is, does the custom validator get associated with the drop down list, or do you put a custom validator on all of the fields a/b/c/d/e/f etc...or is there the concept of a form-level custom validator that I can have called?</p>
  
  <p>Probably at least ten different ways to do this, but looking for the cleanest option.</p>