RequireFieldValidators are easy enough to use with RadioButtonLists and DropDownLists, but not with CheckBoxLists.  What gives? Is there a way to use a RequiredFieldValidator with a CheckBoxList or an easy way to mimic the same functionality?

  thanks,

     Rob
 

The problem with checkboxes is that, unlike the dropdownlist and radiobuttonlist, it is perfectly valid to not have any checkboxes selected (checked)...

Yes there is a way to validate this, just have to determine your own business rules for validation.

The button or whatever that submits the values and must validate the values must have set the attribute CausesValidation  = true..

The validation rules can be describe in the Validate() method of the page. (in your case, check if a checkbox is checked).

In the OnClick event of the button you can call the Validate() method, and check if Page.IsValid == true.

Hope this will give you an idea, there are thousands of good examples on the net and msdn.

On modern browsers this should all be happening client-side

There are also a couple of checkbox extenders in the AJAX toolkit which could be useful to you

See http://www.asp.net/learn/ajax-videos/video-94.aspx and http://www.asp.net/learn/ajax-videos/video-132.aspx

hope this helps!

The validation happenes on the server side (runat="server").

The client side can use AJAX/Java/HTML etc scripts (which were generated on the server)to generate the clientside output (server delivers html/java which updates in specific area in the page, and not the whole page's content), like divs that are set visible or alerts or whatever.

I think it is a very nice way to validate a page. As another member posted, it is valid to have no checkboxes checked. So you have to implement that rule yourself. Which is actually pretty easy to do...

if you use custom validator and leave the controltovalidate property empty, the checkbox will be validated at clientside whenever the page is trying to post back....e.g.. a button click etc

Yes you are right. In this case the custom validator will be page level and will be fired whenever you submit. Let me tell you what is the benefit of having ControlTovalidate, it shows you error mark when the value of the control (set as controltovalidate of the validator)  is invalid and you tab out from that control. But when your controltovalidte is empty in case of custom validator you will have to wait for the errormark until you submit you submit your page (click on submit).

Did this solve your problem?. If yes mark this as answered