[MVC] Pass parameters to ActionFilterAttribute

 ASP.NET    MVC5

▌Introduction

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We will learn how to pass parameters to a custom ActionFilterAttribute by these two ways.

1.  Public properties in ActionFilter

2.  Use ViewBag/ViewData/TempData

▌Environment

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▋Visual Studio 2017 community 15.3.3

▋ASP.NET MVC5

▌Implement

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▋ActionFilter with public properties

▋Implement ActionFilterAttribute

Override OnActionExecuted for example.

public class LogActionFilter : ActionFilterAttribute {         public string PageTitleZh { get; set; }         public string PageTitleCn { get; set; }         public string PageTitleEn { get; set; }         public override void OnActionExecuted(ActionExecutedContext filterContext)         {             base.OnActionExecuted(filterContext);             //Log(PageTitleZh, PageTitleCn, PageTitleEn)         } }

▋Usage in MVC Controller

[HttpPost] [LogActionFilter(PageTitleZh = "XXXX", PageTitleCn ="YYYY", PageTitleEn =  "ZZZZ")] [ValidateAntiForgeryToken] public async Task<ActionResult> Create(VmModel viewModel) { }

However, if we want to pass parameters with dynamic values, we have to use the next approach.

▋Get parameter thru ViewData/ViewBag/TempData in ActionFilter

We will use ViewData for example.

▋MVC Controller

[HttpPost] [LogActionFilter]        [ValidateAntiForgeryToken] public async Task<ActionResult> Create(VmModel viewModel) {      ViewData["PageTitleZh"] = "MVC進階課程";      ViewData["PageTitleCn"] = "MVC进阶课程";      ViewData["PageTitleEn"] = "MVC advanced class"; }

▋Implement ActionFilterAttribute

public class LogActionFilter : ActionFilterAttribute {         public override void OnActionExecuted(ActionExecutedContext filterContext)         {             base.OnActionExecuted(filterContext);                         var httpContext = filterContext.RequestContext.HttpContext;             var viewData = filterContext.Controller.ViewData;                        Log(new TraceLog             {                 PageTitleZh = (string)viewData["PageTitleZh"] ?? "",                 PageTitleCn = (string)viewData["PageTitleCn"] ?? "",                 PageTitleEn = (string)viewData["PageTitleEn"] ?? "",                 PageUri = httpContext.Request.Path,                 UserId = httpContext.User.Identity.Name,                 UserIp = httpContext.Request.UserHostAddress             });         } }

▌Reference

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▋How do I pass variables to a custom ActionFilter in ASP.NET MVC app