How to display alert message box in asp.net core mvc controller?

Question

I want to display alert message box when the account model is invalid. How should i gonna do this in controller in Asp.Net Core MVC? Here is my Controller's code

    [HttpPost]
    public IActionResult Index(Account model)
    {
        if (model.ID != null && model.PassWord != null)
        {
            using (var db = new AccountDBContext())
            {
                var account = db.Account.FirstOrDefault(
                                a => a.ID.Equals(model.ID) && a.PassWord.Equals(model.PassWord)
                              );

                if(account != null)
                    return RedirectToAction("Index", "Main");       

            }
            //I want to display error msg box...here like "Check ID or PW".
            ModelState.AddModelError("", "Error");

        }


        return View();
    }

I searched the way but there is no "Page" identifier or "Response.write()" Method in this controller class.... How should i gonna do?

p.s The way that i checked model's validation like that is right way? (I used a model and check it's partial properties, instead using view model )

Isma · Accepted Answer · 2017-09-11 08:43:18Z

7

Define the error in your controller:

ModelState.AddModelError("Error", "Check ID");

And then display it in the view:

@if (!ViewData.ModelState.IsValid && ViewData.ModelState["Error"].Errors.Count > 0)
{
    <div class="alert alert-
       <strong>Error!</strong> danger">@ViewData.ModelState["Error"].Errors.First().ErrorMessage
    </div>
}

EDIT

To show an alert box, add some javascript in your view, the following uses jquery:

<head>
    <script type="text/javascript">
        @if (!ViewData.ModelState.IsValid && ViewData.ModelState["Error"].Errors.Count > 0)
        {
            <text>
            $(document).ready(function() {
                alert('@ViewData.ModelState["Error"].Errors.First().ErrorMessage');
            });
            </text>
        }
    </script>
</head>

edited Sep 11, 2017 at 8:43

answered Sep 11, 2017 at 7:25

Isma

15.3k5 gold badges42 silver badges54 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

user3559349 Over a year ago

OP has asked how to do it using an alert message box

HelloWorld Over a year ago

Thanks for answering! but i put below if it is not valid. <script> alert('@Html.ValidationMessage("Error")')</script> Then there is an error occured like this. <span class="field-validation-valid" data-valmsg-for="Error" data-valmsg-replace="true"></span>

Isma Over a year ago

I fixed a small bug, I just tested it and should do what you want ;)

HelloWorld Over a year ago

Oh Thanks a lot!! (p.s : May i ask ViewData.ModelState["Error"].Errors.Count meaning?)

Collectives™ on Stack Overflow

How to display alert message box in asp.net core mvc controller?

1 Answer 1

4 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related