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Accepted
Franqo Balsamo
Asked: 2020-04-30 05:56:30 +0800 CST 2020-04-30 05:56:30 +0800 CST

Alert in MVC c#

  • 772

I have a question, how do I show an alert in MVC? I am validating from the controller the following:

var suscriptor = c.cargarDatosPDF(solicitud);
                if (suscriptor.Count <= 0)
                {
                    ViewBag.Alert = "Lo sentimos, esta solicitud no existe.";
                    return View("Index");
                }

That list is loaded with data from SQL. I would like that message to be seen in a PopUpor Alert, preferably a alert. He Indexhas a TextBoxand a Botón.

I tried using:

alert(@ViewData["Mensaje"])

But, it hasn't worked. Any suggestion?

Update:

Index:

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Inicio</title>
    <link rel="stylesheet" type="text/css" href="~/Estilos/inicio.css">
    <script type="text/javascript" src="~/JavaScript/validar.js"></script>
    <script type="text/javascript"></script>
</head>
<body>
    <center>
        <div class="topnav" style="width: 350px">
            <a title="Providus S.A" href="http://www.providus.com.ar"><img src="~/Images/00.png" /></a>
        </div>
        <div style="width: 350px">
            <form method="post" action="@Url.Action("Pdf", "Home")">
                <label for="solicitud">Solicitud: </label>
                <input type="text" id="solicitud" minlength="5" maxlength="7" name="solicitud" placeholder="Solicitud..." required
                       title="Sólo letras y números. Cantidad mínima de caracteres: 5. Cantidad máxima de caracteres: 7"
                       onkeypress="return soloLetrasYnumeros(event)">

                <input type="submit" value="Buscar" />
            </form>
        </div>
    </center>
    @if (ViewBag.Alert != null)
    {
        <div class="alert alert-dismissable alert-info">
            <button type="submit" class="close" data-dismiss="alert">
                &times;
            </button>
            <strong>Providus informa...</strong> @ViewBag.Alert
        </div>
    }
    @*<center>
        <p class="mensaje">@ViewData["Mensaje"]</p>
    </center>*@
</body>
</html>
c#

2 Answers

  1. First of all, the way you propose to change the message of the Javascript Alert box I inform you that it is not possible, if you want a personalized alert message you must look for an alternative, one can be using jQuery ( https://labs.abeautifulsite.net/ archived/jquery-alerts/demo/ )

    Another and simpler way is to define in your View or in the _Layout (shared view (Shared) of all views) a ViewBag.Alert and printing the necessary message in each case.

     @if (ViewBag.Alert != null)
 {
     <div class="alert alert-dismissable alert-info">
         <button type="button" class="close" data-dismiss="alert">
             &times;
         </button>
         <strong>Aviso!</strong> @ViewBag.Alert
     </div>
 }

    And in your C# code you would pass the following message:

    var suscriptor = c.cargarDatosPDF(solicitud);
                if (suscriptor.Count <= 0)
                {
                    ViewBag.Alert = "Lo sentimos, esta solicitud no existe.";
                    return View("Index");
                }

    Another way is using a Modal ( https://getbootstrap.com/docs/4.0/components/modal/ ), where you would have to use some Javascript to do the sampling.

    • 2
  2. Best Answer

    If what you want is a alert()simple javascript, the example that they have already given you is valid, making a small change. In the view, try adding this code:

    @if (ViewBag.Alert != null)
{
  <script>
    alert("@ViewBag.Alert");
  </script>
}

    This code should be added to the end of the view.

    • 1