问删除Umbraco的通知并显示我自己的通知

EN

using Umbraco.Core;
public class CustomNotificationsRegistration : IApplicationEventHandler
{
    public void OnApplicationInitialized(UmbracoApplicationBase umbracoApplication,
        ApplicationContext applicationContext)
    { }

    public void OnApplicationStarting(UmbracoApplicationBase umbracoApplication,
        ApplicationContext applicationContext)
    {
        System.Web.Http.GlobalConfiguration.Configuration.MessageHandlers.Add(new WebApiHandler());
    }

    public void OnApplicationStarted(UmbracoApplicationBase umbracoApplication,
        ApplicationContext applicationContext)
    {
    }
}

using System;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using Umbraco.Core.Logging;
using Umbraco.Web.Models.ContentEditing;
using Umbraco.Web.UI;
public class WebApiHandler : System.Net.Http.DelegatingHandler
{
    protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        if (request.RequestUri.AbsolutePath.ToLower() == "/umbraco/backoffice/umbracoapi/content/postsave")
        {
            return base.SendAsync(request, cancellationToken)
                .ContinueWith(task =>
                {
                    var response = task.Result;
                    try
                    {
                        var data = response.Content;
                        var content = ((ObjectContent)(data)).Value as ContentItemDisplay;

                        //perform any checking (if needed) to ensure you have the right request
                        //for us the cancellation of publish  was only on one content type so we could narrow that down here 
                        if (content.ContentTypeAlias.Equals("[My content type alias]"))
                        {
                            if (content.Notifications.Count > 0)
                            {
                                foreach (var notification in content.Notifications)
                                {
                                    if (notification.Header.Equals("Content Published"))
                                    {
                                        //change the default notification to our custom message
                                        notification.Header = "[Custom Header Message]";
                                        notification.Message = "[Custom Message]";
                                        notification.NotificationType = SpeechBubbleIcon.Sucess;
                                    }
                                }
                            }
                        }
                    }
                    catch (Exception ex)
                    {
                        //log the error
                    }
                    return response;
                });
        }

        return base.SendAsync(request, cancellationToken);
    }
}