DerombaB.AspNetCore.FlashExtensions 1.0.0

How to use

From Controller/PageModel :

public async Task<IActionResult> OnGet()
{
    ...
    return RedirectToPage("./Index")
        .WithSuccessFlash("Success title", "Success body")
        .WithInfoFlash("Info title", "Info body")
        .WithWarningFlash("Warning title", "Warning body")
        .WithDangerFlash("Danger title", "Danger body");
}

There is also a .WithFlash(string type, string title, string body) to use custom types of flash messages. Those methods are extensions of IActionResult and can be used then on any type of ActionResult.

And then from Page/View (the following code uses BS4 classes for dismissible alert) :

...
@{
    var flashMessages = TempData.GetFlashMessages();
}
@if(flashMessages != null)
{
    @foreach (var flashMessage in flashMessages)
    {
        <div class="alert alert-@flashMessage.Type alert-dismissible" role="alert">
            <button type="button" class="close" data-dismiss="alert" aria-label="Close">
                <span aria-hidden="true">&times;</span>
            </button>
            <strong>@flashMessage.Title</strong> @flashMessage.Body
        </div>
    }
}
...

PS: The call to .GetFlashMessages() function frow view to display the data end up cleaning all the flash messages of the list, not only the displayed ones.