ViewRendererServiceController.cs

using System.Threading.Tasks;
using DNTCommon.Web.Core.TestWebApp.Models;
using Microsoft.AspNetCore.Mvc;

namespace DNTCommon.Web.Core.TestWebApp.Controllers
{
    public class ViewRendererServiceController : Controller
    {
        private readonly IViewRendererService _viewRendererService;

        public ViewRendererServiceController(IViewRendererService viewRendererService)
        {
            _viewRendererService = viewRendererService;
        }

        public IActionResult Index()
        {
            return View();
        }

        public async Task<IActionResult> Render()
        {
            var content = await _viewRendererService.RenderViewToStringAsync(
                viewNameOrPath: "~/Views/EmailTemplates/_Template1.cshtml",
                model: new EmailTemplateViewModel
                {
                    EmailSignature = "DNT"
                });
            return Content(content);
        }
    }
}