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divyanshm
divyanshm

Reputation: 6800

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

I have a controller in my MVC app for which I'm trying to log details using a custom ActionFilterAttribute, by using the onResultExecuted method.

I read this tutorial to understand and write my own action filter. The question is how do I pass variables from the controller to the action filter?

  1. I want to get the input variables with which a controller is called. Say, the username/user ID.
  2. If (in some situations) an exception is thrown by any controller method, I would want to log the error too.

The controller - 

[MyActionFilter]
public class myController : ApiController {
    public string Get(string x, int y) { .. }
    public string somemethod { .. }
}

The action filter - 

public class MyActionFilterAttribute : ActionFilterAttribute {
    public override void onActionExecuted(HttpActionExecutedContext actionExecutedContext) {
        // HOW DO I ACCESS THE VARIABLES OF THE CONTROLLER HERE
        // I NEED TO LOG THE EXCEPTIONS AND THE PARAMETERS PASSED TO THE CONTROLLER METHOD
    }
}

I hope I have explained the problem here. Apologies if I'm missing out some basic objects here, I'm totally new to this.

Upvotes: 27

Views: 38956

Answers (2)

Peyman Majidi
Peyman Majidi

Reputation: 1985

I suggest another approach, and it is passing parameters to Action Filter as constractor.

[PermissionCheck(Permissions.NewUser)]
public ActionResult NewUser()
{
 // some code
}

Then in the ActionFilter:

public class PermissionCheck : ActionFilterAttribute
{
    public Permissions Permission { get; set; }
    public PermissionCheck(Permissions permission)
    {
        Permission = permission;
    }
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        
        
        if (/*user doesn't have that permission*/)
        {

            filterContext.Result = new RedirectToRouteResult
           (
               new RouteValueDictionary
                   (
                       new {
                           controller = "User",
                           action = "AccessDeny",
                           error = "You don't have permission to do this action"
                       }
                   )
           );
            base.OnActionExecuting(filterContext);
        }
    }
}

Which Permissions is an ENUM like:

enum Permissions {NewUser, Edit, Delete, Update, ...}

Upvotes: 0

Chamaququm
Chamaququm

Reputation: 6728

Approach - 1

Action Filter

public class MyActionFilter : ActionFilterAttribute
{
    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        base.OnActionExecuted(filterContext);
    }
}

Action Method

[MyActionFilter]
public ActionResult Index()
{
    ViewBag.ControllerVariable = "12";
    return View();
}

enter image description here

If you pay attention to the screenshot, you can see the ViewBag information

Approach - 2

Action Filter

public class MyActionFilter : ActionFilterAttribute
{
    //Your Properties in Action Filter
    public string Property1 { get; set; }
    public string Property2 { get; set; }

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        base.OnActionExecuting(filterContext);
    }
}

Action Method

[MyActionFilter(Property1 = "Value1", Property2 = "Value2")]
public ActionResult Index()
{
    return View();
}

Upvotes: 75

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