ASP.NET MVC How to convert ModelState errors to json

Question

How do you get a list of all ModelState error messages? I found this code to get all the keys: ( Returning a list of keys with ModelState errors)

var errorK         


        

Answer 1

Here is the full implementation with all the pieces put together:

First create an extension method:

public static class ModelStateHelper
{
    public static IEnumerable Errors(this ModelStateDictionary modelState)
    {
        if (!modelState.IsValid)
        {
            return modelState.ToDictionary(kvp => kvp.Key,
                kvp => kvp.Value.Errors
                                .Select(e => e.ErrorMessage).ToArray())
                                .Where(m => m.Value.Any());
        }
        return null;
    }
}

Then call that extension method and return the errors from the controller action (if any) as json:

if (!ModelState.IsValid)
{
    return Json(new { Errors = ModelState.Errors() }, JsonRequestBehavior.AllowGet);
}

And then finally, show those errors on the clientside (in jquery.validation style, but can be easily changed to any other style)

function DisplayErrors(errors) {
    for (var i = 0; i < errors.length; i++) {
        $("")
        .html(errors[i].Value[0]).appendTo($("input#" + errors[i].Key).parent());
    }
}