Facebook API Question posted in
The official documentation for the Facebook APIs can be found here.

How do I pass parameters from action filters to the controllers actions in MVC? – Facebook api

It has been a day trying to figure out how to pass parameters from action filter to the controllers actions but with no luck. I have been to this SO question and tried both of the answers.
When I debug my application I don’t get a value for my controller action parameter it is always null.

Here is the action filter…

public class FacebookCheckPermission : ActionFilterAttribute
    {
        public string redirectURL { get; set; }
        public async  override void OnActionExecuting(ActionExecutingContext filterContext)
        {
                var myBaseController = (BaseController)filterContext.Controller;
                PermissionRequestViewModel permissionViewModel = myBaseController.GetMissingPermissions();

                filterContext.RouteData.Values.Add("Value1", "Hi");

                filterContext.ActionParameters["Value2"] = "Bye";

                if (permissionViewModel != null &&
                    permissionViewModel.MissingPermissions.Count > 0)
                //Code removed for brevity.

                base.OnActionExecuting(filterContext);
        }

    }

And here is the Controller Action:

[FacebookCheckPermission]
public async Task<ActionResult> Index(string Value1, string Value2)
{

UPDATE
Seems that I have found the problem. The problem is that my Action filter is async and I have some API calls to facebook. I can get my action filter parameter if I declare it anywhere before the API calls but when I declare it under an API call my action parameter become null. What could be the problem?

Here is the call to facebook graph API.
dynamic myInfo = await fb.GetTaskAsync("me?fields=id,first_name,last_name,link,locale,email,name,birthday,gender,location,age_range,about".GraphAPICall(appsecret_proof));

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2

Answers


  1. 0

    Use ActionParameters

     public class FacebookCheckPermission : ActionFilterAttribute
    {
        public string redirectURL { get; set; }

        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            filterContext.ActionParameters["Value1"] = "Hi";
            filterContext.ActionParameters["Value2"] = "Bye";

            base.OnActionExecuting(filterContext);
        }

    }

        [FacebookCheckPermission]
        public Task<ActionResult> Index(string Value1, string Value2)
        {
            string lol = $"{Value1} - {Value2}";
            return null;

        }

    Use simple adding ActionParameters first, that works fine, then add other codes, there is not any problem with ActionParameters.

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  2. 0

    You can also use RouteData values.

    protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
    filterContext.RouteData.Values.Add("MyParam", "ParamValue");
}

    Then in the controller.

       var paramValue = RouteData.Values["MyParam"].ToString();

    There is a “clunkier” method… I’ve put a private var at the top of the controller, assigned to this in OnActionExecuting and then used that var in my action method.

    Hope that helps.

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