Logo Questions Linux Laravel Mysql Ubuntu Git Menu
 

How to handle ASP.NET MVC3 Request Validation exceptions as model or property validation errors

My question is hopefully pretty straight forward. Upon submitting my form, I would like to flag all properties (fields) that have invalid characters (specifically HTML) as model errors. The issue I am facing is that Request Validation kicks in before model binding/validation and I get HTTP 500... I saw a similar question that advertises either using [AllowHtml] property attribute on your Model/ViewModel or using <httpRuntime requestValidationMode="2.0" /> in web.config, but what I am looking for is how to "globally catch Request Validation exceptions and show them as model errors". Furthermore, I don't want to "strip" HTML tags, I want to notify the user that their input is not valid.

I thought about using Regular Expression validation attributes to find bad input, but as I mentioned, the Request Validation on ASP.NET MVC3 occurs before model binding/validation, so that is a no-go...

A really good overview of the Request Validation can be found here.

like image 447
zam6ak Avatar asked Feb 13 '12 14:02

zam6ak


1 Answers

I think your only intention is to get the Request Validation exception during model binding and show the errors as model state error. Here is the sample,

    using System.Web.Helpers;
    public class MyModelBinder : DefaultModelBinder
    {
        public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
        {
            try
            {
                return base.BindModel(controllerContext, bindingContext);
            }
            catch(HttpRequestValidationException ex)
            {
                var modelState = new ModelState();
                modelState.Errors.Add(ex.Message);
                var key=bindingContext.ModelName;
                var value = controllerContext.RequestContext.HttpContext.Request.Unvalidated().Form[key];
                modelState.Value = new ValueProviderResult(value, value,CultureInfo.InvariantCulture);
                bindingContext.ModelState.Add(key, modelState);
            }
            return null;
        }
    }

    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();
        ModelBinders.Binders.DefaultBinder = new MyModelBinder();
    }

This will add the exception of only request validation in model state. Sorry, If I don't understand your question clearly.

like image 149
imran_ku07 Avatar answered Sep 30 '22 08:09

imran_ku07