Chapter104:ActionFilters

Section104.1:CustomActionFilters

We write custom action filters for various reasons. We may have a custom action filter for logging, or for saving data to database before any action execution. We could also have one for fetching data from the database and setting it as the global values of the application.

Tocreateacustomactionfilter,weneedtoperformthefollowingtasks:

1. Createaclass
2. InherititfromActionFilterAttributeclass

Overrideatleastoneofthefollowingmethods:

OnActionExecuting–Thismethodiscalledbeforeacontrolleractionisexecuted.

OnActionExecuted–This method is called after a controller action is executed.

OnResultExecuting–This method is called before a controller action result is executed. OnResultExecuted–This method is called after a controller action result is executed.

Thefiltercanbecreatedasshowninthelistingbelow:

usingSystem;

usingSystem.Diagnostics;

usingSystem.Web.Mvc;

namespaceWebApplication1

{

publicclassMyFirstCustomFilter:ActionFilterAttribute

{

publicoverridevoidOnResultExecuting(ResultExecutingContextfilterContext)

{

//Youmayfetchdatafromdatabasehere filterContext.Controller.ViewBag.GreetMesssage=”HelloFoo”;base.OnResultExecuting(filterContext);

}

publicoverridevoidOnActionExecuting(ActionExecutingContextfilterContext)

{

varcontrollerName=filterContext.RouteData.Values[“controller”]; varactionName=filterContext.RouteData.Values[“action”];

varmessage=String.Format(“{0}controller:{1}action:{2}”,”onactionexecuting”,

controllerName,actionName);

Debug.WriteLine(message,”ActionFilterLog”);

base.OnActionExecuting(filterContext);

}

}

}