FlashHelper.cs

FlashHelper.cs

using Newtonsoft.Json;
using System;
using System.Web;
using System.Web.Mvc;

public static class FlashHelper
{
    public static ActionResult WithInfo(this ActionResult actionResult, ControllerBase controller, string title = "", string message = "")
    {
        AddMessageToTempData(controller, AlertType.Info, title, message);
        return actionResult;
    }

    public static ActionResult WithSuccess(this ActionResult actionResult, ControllerBase controller, string title = "", string message = "")
    {
        AddMessageToTempData(controller, AlertType.Success, title, message);
        return actionResult;
    }

    public static ActionResult WithWarning(this ActionResult actionResult, ControllerBase controller, string title = "", string message = "")
    {
        AddMessageToTempData(controller, AlertType.Warning, title, message);
        return actionResult;
    }

    public static ActionResult WithError(this ActionResult actionResult, ControllerBase controller, string title = "", string message = "")
    {
        AddMessageToTempData(controller, AlertType.Error, title, message);
        return actionResult;
    }

    public static void FlashInfo(this ControllerBase controller, string title = "", string message = "")
    {
        AddMessageToTempData(controller, AlertType.Info, title, message);
    }

    public static void FlashSuccess(this ControllerBase controller, string title = "", string message = "")
    {
        AddMessageToTempData(controller, AlertType.Success, title, message);
    }

    public static void FlashWarning(this ControllerBase controller, string title = "", string message = "")
    {
        AddMessageToTempData(controller, AlertType.Warning, title, message);
    }

    public static void FlashError(this ControllerBase controller, string title = "", string message = "")
    {
        AddMessageToTempData(controller, AlertType.Error, title, message);
    }

    public static MvcHtmlString RenderAlert(this HtmlHelper helper)
    {
        object alertData = helper.ViewContext.TempData["alert"];

        if (alertData == null)
            return MvcHtmlString.Empty;

        var alert = new AlertMessage(alertData.ToString());

        if (String.IsNullOrEmpty(alert.Message) && String.IsNullOrEmpty(alert.Title))
            return MvcHtmlString.Empty;
        return
            new MvcHtmlString(String.Format(
                "<div class='alert alert-{0} alert-dismissable'><button type='button' class='close' data-dismiss='alert' aria-hidden='true'>&times;</button><strong>{1}</strong>{2}</div>",
                alert.CssClass, HttpUtility.HtmlEncode(alert.Title), HttpUtility.HtmlEncode(alert.Message)));
    }

    private static void AddMessageToTempData(ControllerBase controller, AlertType type, string title, string message)
    {
        var alertMessage = new AlertMessage
        {
            Title = title,
            Message = message,
            CssClass = type.CssClass
        };

        controller.TempData["alert"] = alertMessage.AsJson();
    }

    internal class AlertType
    {
        public string CssClass { get; private set; }

        public AlertType(string cssClass)
        {
            CssClass = cssClass;
        }

        public static AlertType Success = new AlertType("success");
        public static AlertType Info = new AlertType("info");
        public static AlertType Warning = new AlertType("warning");
        public static AlertType Error = new AlertType("danger");
    }

    internal class AlertMessage
    {
        public string Title { get; set; }
        public string Message { get; set; }
        public string CssClass { get; set; }

        public AlertMessage() { }
        public AlertMessage(string json)
        {
            var alertMessage = JsonConvert.DeserializeObject<AlertMessage>(json);

            Title = alertMessage.Title;
            Message = alertMessage.Message;
            CssClass = alertMessage.CssClass;
        }

        public string AsJson()
        {
            return JsonConvert.SerializeObject(this);
        }
    }
}