How to customize Html.ValidationMessageFor in ASP MVC

Question

Is it possible to customize the Html.ValidationMessageFor method so that it produces different HTML?

I want to do something similar to:

<div class="field-error-box">     <div class="top"></div>     <div class="mid"><p>This field is required.</p></div> </div> 

Answer 1

I am not sure if it's possible to use paragraph instead of default span, as it may make impossible for validation plugin to place error messages. But for div -s, thats easy - you could write custom html helper.

Something along these lines (may need further testing/coding). You will need to include the namespace of this static extension method in your view, or put this into System.Web.Mvc.Html directly.

public static class Validator {     public static MvcHtmlString MyValidationMessageFor<TModel, TProperty>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression)     {         TagBuilder containerDivBuilder = new TagBuilder("div");         containerDivBuilder.AddCssClass("field-error-box");          TagBuilder topDivBuilder = new TagBuilder("div");         topDivBuilder.AddCssClass("top");          TagBuilder midDivBuilder = new TagBuilder("div");         midDivBuilder.AddCssClass("mid");         midDivBuilder.InnerHtml = helper.ValidationMessageFor(expression).ToString();          containerDivBuilder.InnerHtml += topDivBuilder.ToString(TagRenderMode.Normal);         containerDivBuilder.InnerHtml += midDivBuilder.ToString(TagRenderMode.Normal);          return MvcHtmlString.Create(containerDivBuilder.ToString(TagRenderMode.Normal));     } } 

As you see, this uses default ValidationMessageFor method, to not interfere with validation-plugin error message processing.

And you use this simply, as default validation message helper

@Html.MyValidationMessageFor(model => model.SomeRequiredField)