Question

I’m building an ASP.NET MVC application with a form that needs validation. The majority of the form is static, but part of the form is dynamic.

I need to enable the user to enter n string/date combinations.

The string/date combos need to be validated server side, and I need to give feedback to the user preferably directly beside the combination that failed validation.

For static input I do the following:

   <%= Html.ValidationMessage('someField') %> 

For the dynamic data, what should I do?

Answer 1

In your controller you’ll want to assign an error to the particular fields that fail validation:

ModelState.AddModelError ('textbox1', 'You must specify a valid string.'); ModelState.AddModelError ('combobox1', 'You must specify a valid date.'); 

Then all the helper is really doing is checking if the following exists:

ViewData.ModelState.ContainsKey('textbox1') 

and then creating a tag such as follows

<span><%= ViewData.ModelState.ContainsKey('textbox1').Errors[0] %></span> 

the helper does a bit more null value checking but you get the idea.