Question

I am using the MvcContrib Grid to display a table on the page. I am using a custom column to produce a checkbox on the table so that the user can select multiple rows and submit the form.

I don’t want the form to submit unless at least one checkbox has been selected. I could easily write this Javascript myself to enforce the validation, but I wanted to know how I could fit it in with the unobtrusive library supplied with MVC3.

I imagine I just need to set my inputs with the proper classes and attributes and then the scripts (validate and validate.unobtrusive) on the page should pick them up and mark them as needing validation, but I haven’t been able to get the right combination thus far.

Here is the input that I am currently generating:

<input type="checkbox" 
       name="foo" 
       value="@item.foo" 
       class="input-validation-error" 
       data-val-required="Please select an option." 
       data-val="true" />

Answer 1

Try setting the data-val attributes on the item, then you have to tell jQuery you have new content to re-parse the form via something like:

 $.validator.unobtrusive.parse($('#yourForm'));

where form is of course a reference to your form element.

There is also this great posting and jQuery has a few internal adapters you can call:
from http://www.devtrends.co.uk/blog/the-complete-guide-to-validation-in-asp.net-mvc-3-part-2

jQuery.validator.unobtrusive.adapters.addSingleVal("notequalto", "otherproperty", "mynotequaltofunction")