Show different View Data in view with different class in ASP.NET Core

This is my controller:

  public async Task<IActionResult>ActiveEmailAccount(EmailActiveAccountViewModel active)
    {
        if (ModelState.IsValid)

        {
            var result = await _userService.ActiveAccount(active);
            switch (result)
            {
                case ActiveEmailResult.Error:
                    ModelState.AddModelError("CustomError", "You Have Error ");
                    break;

                case ActiveEmailResult.NotActive:
                    ModelState.AddModelError("CustomError", "You Are not Active. ");
                    break;

                case ActiveEmailResult.Success:
                    ModelState.AddModelError("CustomError", "You Are Active ");
                 
                    break;
            }

            ViewData["Active"] = result;
        }

        return View(active);

}

I want to show result of View data in view. I know it is

<p> @(ViewData["Active"] </P>

I want to know how can I show these results in different status with different class?

for example if was success: with class="alert-success"

if was not active with class alert-danger.....

Inside the switch-case statement in your action you can set a ViewData entry with the alert class for each case:

public async Task<IActionResult> ActiveEmailAccount(EmailActiveAccountViewModel active)
{
    if (ModelState.IsValid)
    {
        var result = await _userService.ActiveAccount(active);

        switch (result)
        {
            case ActiveEmailResult.Error:
                ModelState.AddModelError("CustomError", "You Have Error ");
                ViewData["AlertClass"] = "alert-danger";
                break;

            case ActiveEmailResult.NotActive:
                ModelState.AddModelError("CustomError", "You Are not Active. ");
                ViewData["AlertClass"] = "alert-warning";
                break;

            case ActiveEmailResult.Success:
                ModelState.AddModelError("CustomError", "You Are Active ");
                ViewData["AlertClass"] = "alert-success";
                break;
        }

        // this is not needed for this scenario
        //ViewData["Active"] = result;
    }

    return View(active);
}

Then in your view you can use Html.ValidationMessage html helper to get the model state message and ViewData to get the alert class:

<div class="alert @ViewData["AlertClass"]">
    @Html.ValidationMessage("CustomError")
</div>

Razor solution:

You can use a switch-case statement inside your view:

@switch ((ActiveEmailResult)ViewData["Active"])
{
    case ActiveEmailResult.Error:
        <div class="alert alert-danger">@Html.ValidationMessage("CustomError")</div>
        break;

    case ActiveEmailResult.NotActive:
        <div class="alert alert-warning">@Html.ValidationMessage("CustomError")</div>
        break;

    case ActiveEmailResult.Success:
        <div class="alert alert-success">@Html.ValidationMessage("CustomError")</div>
        break;
}