How to display error message as a modal

Question

I'm trying to display a error massage as a modal boostrap... the message is sent correctly but the partial view load as common page... (no modal)

I need your help to solve this.. :)

return RedirectToAction("ShowError", new { sErrorMessage = "Error Message" });

This is my ActionResult 'ShowError'

 public ActionResult ShowError(String sErrorMessage)
    {
        ViewBag.sErrMssg = sErrorMessage;
        return PartialView("ErrorMessageView");
    }

My PartialView 'ErrorMessageView'

<div class="modal fade" tabindex="-1" role="dialog">
<div class="modal-dialog" role="document">
    <div class="modal-content">
        <div class="modal-header">
            <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
            <h4 class="modal-title">Error</h4>
        </div>
        <div class="modal-body">
          @ViewBag.sErrMssg
        </div>
        <div class="modal-footer">
            <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
            <button type="button" class="btn btn-primary">Save changes</button>
        </div>
    </div><!-- /.modal-content -->
</div><!-- /.modal-dialog -->

Solution

You could try the following solution:

1. Instead of using ViewBag use TempData["sErrMsg"] - using TempData retains the value accross the current and the subsequent HTTP request.
2. In the controller action - set TempData["sErrMsg"] to the required error message if a specific condition is met.
3. In the View - check if the TempData["sErrMsg"] has a value (contains an error) and if it does use Html.RenderPartial("ErrorMessageView", TempData["sErrMsg"]); to render the partial view as a bootstrap modal popup.

Controller:

public class ProductController : Controller
{
    public ActionResult Index()
    {
        return View();
    }

    public ActionResult Save(string name)
    {
        if(String.IsNullOrEmpty(name))
            TempData["sErrMsg"] = "Product name cannot be empty";

        return View("Index");
    }

    public PartialViewResult ShowError(String sErrorMessage)
    {
        return PartialView("ErrorMessageView");
    }
}

Index View:

@using (Html.BeginForm("Save", "Product", FormMethod.Post, new { id = "myform" }))
{
    @Html.TextBox("name", null, new { style = "width:500px;" })
    <input type="submit" value="Add" />
}

@if (TempData["sErrMsg"] != null)
{
    Html.RenderPartial("ErrorMessageView", TempData["sErrMsg"]);
}

Partial Error View:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.3/jquery.min.js"></script>
<script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" />

<script type="text/javascript">
    $(function () {
        $('.modal').modal('show');
    });
</script>
<div class="modal fade" tabindex="-1" role="dialog">
    <div class="modal-dialog" role="document">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
                <h4 class="modal-title">Error</h4>
            </div>
            <div class="modal-body">
                @Model
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                <button type="button" class="btn btn-primary">Save changes</button>
            </div>
        </div>
    </div>
</div>