Check if Validation Message Exists ASP.Net MVC 5

Question

Is there a way to check if Validation Message exists for a particualr field in ASP.Net MVC 5. I need to check this in Razaor form

Currently is IsNullOrEmpty but i think ValidationMessage does return some html tags even if there are no validation errors ?

I need to show a div only if a Validation Message Exists i.e. validation has failed for that for a particaulr field.

Answer 1

You can access the ModelState through a property of ViewData in order to check for validation errors before outputting any HTML:

 @if(!ViewData.ModelState.IsValid) {
      @Html.ValidationMessageFor(...)
 }

Edit: or, if you're wanting to check a specific property:

 @if(ViewData.ModelState["PropertyName"] != null && ViewData.ModelState["PropertyName"].Errors.Any()) {
       @Html.ValidationMessageFor(...)
  }

Answer 2

This is the span created by @ValidationMessagefor() :

<span class="field-validation-error" data-valmsg-for="FieldName" data-valmsg-replace="true"><span for="FieldName" generated="true" class="">Field name is required.</span></span>

You can just check class "field-validation-error" whether it exists or not.

Answer 3

This is a pretty dumb test, but usually sufficient, and has the added benefit of utilizing Intellisense in Visual Studio:

1. Create Project/Helpers/HtmlHelper.cs as a new class

   using System.Web.Mvc;
   using System.Web.Mvc.Html;
   
   namespace Project.Helpers
   {
       public static class HtmlHelper
       {
           public static bool HasValidationMessageFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression)
           {
               var value = htmlHelper.ValidationMessageFor(expression).ToString();
   
               return value.Contains("field-validation-error");
           }
       }
   }
   

2. Add that namespace to Views/Web.config:

   <configuration>
     <system.web.webPages.razor>
       <pages pageBaseType="System.Web.Mvc.WebViewPage">
         <namespaces>
           <add namespace="Project.Helpers" />
   

3. Close and reopen the solution in Visual Studio, which I had to to for VS 2013 or Intellisense didn't pick up the new HTML helper in my Razor views

4. Use it:

   @if (Html.HasValidationMessageFor(model => model.Property))
   {
       @* Do stuff *@
   }
   

Kartikeya's answer provided the markup generated by the Html.ValidatorMessageFor(...) method call:

<span class="field-validation-error" data-valmsg-for="FieldName" data-valmsg-replace="true">
    <span for="FieldName" generated="true" class="">
        Field name is required.
    </span>
</span>

(Code formatting, mine)

And as he said, testing for the field-validation-error class name should work fine.

Answer 4

a) unknown or general custom added error display (non model property specific)

  if (ViewData.ModelState.Any(x => x.Key == string.Empty))
  {
      @Html.ValidationSummary(true, string.Empty, new { @class = "error")
  }

b) model property specific error display

@Html.ValidationMessageFor(m => m.Email, string.Empty, new { @class = "error" })