action filters in mvc ASP.NET MVC-IGI

Action filters are a type of filter in ASP.NET MVC that can be applied to an action method to modify its behavior before or after it is executed. Action filters implement the IActionFilter interface or one of its derivatives (IAsyncActionFilter, ICancellableAsyncActionFilter).

Here are some common scenarios where action filters can be used:

Authentication and authorization - You can use an action filter to perform authentication and authorization checks before an action is executed. If the user is not authorized, you can redirect them to a login page or return an error message.
Logging - You can use an action filter to log information about the action, such as its name, parameters, and execution time.
Caching - You can use an action filter to cache the result of an action, so that it can be returned faster for subsequent requests.
Validation - You can use an action filter to perform validation on the action's parameters or model before the action is executed.
Exception handling - You can use an action filter to catch exceptions that occur during the execution of an action, and return a custom error message or redirect to an error page.

Here is an example of an action filter that logs information about the action:

public class LogActionFilter : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        string actionName = filterContext.ActionDescriptor.ActionName;
        string controllerName = filterContext.ActionDescriptor.ControllerDescriptor.ControllerName;
        string message = String.Format("Executing action {0} in controller {1}", actionName, controllerName);
        Logger.Log(message);
    }

    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        string actionName = filterContext.ActionDescriptor.ActionName;
        string controllerName = filterContext.ActionDescriptor.ControllerDescriptor.ControllerName;
        string message = String.Format("Executed action {0} in controller {1}", actionName, controllerName);
        Logger.Log(message);
    }
}

Source:ww‮.w‬theitroad.com

In this example, the LogActionFilter class implements the IActionFilter interface and overrides the OnActionExecuting and OnActionExecuted methods to log information about the action before and after it is executed. You can apply this filter to an action by adding the [LogActionFilter] attribute to the action method, like this:

[LogActionFilter]
public ActionResult MyAction()
{
    // action code here
}

This will cause the LogActionFilter to be executed before and after the MyAction method is called, logging information about the action to a log file or database.

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action filters in mvc ASP.NET MVC