/Visual Studio 2008/CSASPNETMVCCustomActionFilter/ActionFilters/MessageModifierActionFilter.cs

/****************************** Module Header ******************************\

 * Module Name:  MessageModifierActionFilter.cs

 * Project:              CSASPNETMVCCustomActionFilter

 * Copyright (c) Microsoft Corporation.

 * 

 * The CSASPNETMVCCustomActionFilter sample demonstrates how to use C# codes to 

 * create custom ActionFilters for ASP.NET MVC web application. In this sample,

 * there are two custom ActionFilters, one is used for customizing ViewData

 * before page view result get executed and rendered; another is used for 

 * perform logging within the various events during the processing of custom 

 * ActionFilters.

 * 

 * 

 * This source is subject to the Microsoft Public License.

 * See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.

 * All other rights reserved.

 * 

 * History:

 * * 10/10/2009 1:35 PM Steven Cheng Created

 ***************************************************************************/



using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Web.Mvc;



namespace CSASPNETMVCCustomActionFilter.ActionFilters

{

    public class MessageModifierActionFilter : ActionFilterAttribute

    {

        public override void OnResultExecuted(ResultExecutedContext filterContext)

        {

            // If we modify the ViewData here, changes will not be reflected in the final PageView since it is too late here( Result has already been executed)



        }



        public override void OnResultExecuting(ResultExecutingContext filterContext)

        {

            // This event is a preprocessing event where we can customize the ViewData collection



            ViewResult view = filterContext.Result as ViewResult;

            if (view != null)

            {

                view.ViewData["Message"] = "[Modified by MessageModifierActionFilter.OnResultExecuting]" + view.ViewData["Message"].ToString();

            }

        }

    }

}