ASP Net Core - Adding ViewData values from ActionFilter

ASP Net Core – Adding ViewData values from ActionFilter

By Rami Hamati | .NET, AspNetCore | 0 comment | 12 January, 2019 | 0

Description

In the MVC lifecyle ActionFilter execute just before the action is invoked. These filters are provided with the action context from which we can access and manipulate the controller context.

In this example I will show how to access a service in an action filter, and add data in the ViewData that can be used in the View.cshtml page

Code

public class MyActionFilter : Attribute, IActionFilter
    {
        public void OnActionExecuted(ActionExecutedContext context)
        {

        }

        public void OnActionExecuting(ActionExecutingContext context)
        {
            Controller controller = context.Controller as Controller;

            if (controller != null)
            {
                //getting a service
                IMyService myService = controller.HttpContext.RequestServices.GetService(typeof(IMyService)) as IMyService;
                //injecting values in the ViewData
                controller.ViewData["myservice"] = myService;
            }
        }
    }

public class MyActionFilter : Attribute, IActionFilter

{

public void OnActionExecuted(ActionExecutedContext context)

{

}

public void OnActionExecuting(ActionExecutingContext context)

{

Controller controller = context.Controller as Controller;

if (controller != null)

{

//getting a service

IMyService myService = controller.HttpContext.RequestServices.GetService(typeof(IMyService)) as IMyService;

//injecting values in the ViewData

controller.ViewData["myservice"] = myService;

}

Add the action filter in the controller’s action

public class MyController : Controller
{

    [MyActionFilter]
    public Task Login()
    {
        //logic
        return View();//ViewData will have our object
    }
}