Question

When my page loads my ValidationSummary and ValidationMessageFor(model => model.TestNumbersString) both display the validation error despite just barely loading the page. I have checked that the .css file is referenced in my _Layout.cshtml and the styles exist for it.

Model.cs

[Required]
public string TestNumbersString { get; set; }

HomeController.cs

public ActionResult Index(TestModel model)
{
    return View(model);
}

partialView.cshtml

@using (Html.BeginForm("Index", "Home", FormMethod.Post, new { @class = "form" }))
{
    @Html.TextAreaFor(model => model.TestNumbersString, new { @class = "testBox" })
    @Html.ValidationMessageFor(model => model.TestNumbersString)
}

My Layout I noticed has a number of javascript and css files, but other validation works on the page, AND I know that the site.css is loaded for other parts of the page (but not for my form, but that’s another problem).

_Layout.cshtml

<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>
<link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" />

The troubleshooting I’ve done so far has lead me to find that the class for the validation message is field-validation-error. So I am lead to believe it’s not a .css error (even though the css styling isn’t applying correctly).

I also want to be clear that this is a partial layout. I’m not sure if this would cause additional problems when dealing with validation.

EDIT: Solution

Thanks to @jacqijvv for the solution.

public ActionResult Index()
{
    TestModel model = new TestModel();
    return View(model);
}

[HttpPost]
//We have these separate as this is the design for MVC.
public ActionResult Index(TDMixParametersViewModel model)
{
    if (ModelState.IsValid)
        return View(model);
    else
    {
        model = new TDMixParametersViewModel();
        return View(model);
    }
}

Answer 1

Remove the parameter from the action method call

E.g.

    public ActionResult Index()
    {
        TestModel model = new TestModel();
        return View(model);
    }

That should fix the problem