[c#] How to call another controller Action From a controller in Mvc


As @mxmissile says in the comments to the accepted answer, you shouldn't new up the controller because it will be missing dependencies set up for IoC and won't have the HttpContext.

Instead, you should get an instance of your controller like this:

var controller = DependencyResolver.Current.GetService<ControllerB>();
controller.ControllerContext = new ControllerContext(this.Request.RequestContext, controller);

I need to call a controller B action FileUploadMsgView from Controller A and need to pass a parameter for it.

 Code---its not going to the controller B's FileUploadMsgView().
    In ControllerA
  private void Test()

        {//some codes here
            ViewBag.FileUploadMsg = "File uploaded successfully.";
            ViewBag.FileUploadFlag = "2";

            RedirectToAction("B", "FileUploadMsgView", new { FileUploadMsg = "File   uploaded successfully" });

     In ControllerB receiving part
  public ActionResult FileUploadMsgView(string FileUploadMsg)
         return View();

as @DLeh says Use rather

var controller = DependencyResolver.Current.GetService<ControllerB>();

But, giving the controller, a controlller context is important especially when you need to access the User object, Server object, or the HttpContext inside the 'child' controller.

I have added a line of code:

controller.ControllerContext = new ControllerContext(Request.RequestContext, controller);

or else you could have used System.Web to acces the current context too, to access Server or the early metioned objects

NB: i am targetting the framework version 4.6 (Mvc5)

        public ActionResult First_controller()
            return Redirect("~/File_upload/Second_controller");
        public ActionResult Second_controller()
            return View();

This is exactly what I was looking for after finding that RedirectToAction() would not pass complex class objects.

As an example, I want to call the IndexComparison method in the LifeCycleEffectsResults controller and pass it a complex class object named model.

Here is the code that failed:

return RedirectToAction("IndexComparison", "LifeCycleEffectsResults", model);

Worth noting is that Strings, integers, etc were surviving the trip to this controller method, but generic list objects were suffering from what was reminiscent of C memory leaks.

As recommended above, here's the code I replaced it with:

var controller = DependencyResolver.Current.GetService<LifeCycleEffectsResultsController>();

var result = controller.IndexComparison(model);
return result;

All is working as intended now. Thank you for leading the way.