How to invoke a View Component from controller

Question

Is it possible to invoke a View Component from controller and render it to a string? I am really looking for some code example for this. Any help will be much appreciated.

Answer 1

You can do that but you have to apply following thing as It is render by DefaultViewComponentHelper.

You have to create instance of this and to create that you need IViewComponentSelector and IViewComponentInvokerFactory.

To do this I have done following thing.

public class HomeController : Controller
    {
        Microsoft.AspNet.Mvc.DefaultViewComponentHelper helper = null;
        Microsoft.AspNet.Mvc.Razor.RazorView razorView = null;
        public HomeController(IViewComponentSelector selector,IViewComponentInvokerFactory factory,IRazorPageFactory razorPageFactory,IRazorPageActivator pageActivator,IViewStartProvider viewStartProvider)
        {
            helper = new DefaultViewComponentHelper(selector, factory);
            razorView = new Microsoft.AspNet.Mvc.Razor.RazorView(razorPageFactory, pageActivator, viewStartProvider);           
        }
        public IActionResult Index()
        {                  
            ViewContext context = new ViewContext(ActionContext, razorView, ViewData, null);
            helper.Contextualize(context);
            string st1 = helper.Invoke("My", null).ToString();
            return View();
        }
}

Here is my sample View Component.

 public class MyViewComponent : ViewComponent
    {     

        public MyViewComponent()
        {

        }

        public IViewComponentResult Invoke()
        {
            return Content("This is test");
        }
    }