ASP.NET Core中使用Razor视图引擎渲染视图为字符串

IViewRenderService

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;

namespace AssemblyPartLIb
{
    public interface IViewRenderService
    {
        Task RenderViewToStringAsync(string viewName, object model);
    }
}

ViewRenderService

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Abstractions;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.Razor;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Routing;
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Threading.Tasks;

namespace AssemblyPartLIb
{
    public class ViewRenderService : IViewRenderService
    {
        private readonly IRazorViewEngine _razorViewEngine;
        private readonly ITempDataProvider _tempDataProvider;
        private readonly IServiceProvider _serviceProvider;
        public ViewRenderService(IRazorViewEngine razorViewEngine,
            ITempDataProvider tempDataProvider,
            IServiceProvider serviceProvider)
        {
            _razorViewEngine = razorViewEngine;
            _tempDataProvider = tempDataProvider;
            _serviceProvider = serviceProvider;
        }

        public async Task RenderViewToStringAsync(string viewName, object model)
        {
            var httpContext = new DefaultHttpContext { RequestServices = _serviceProvider };
            var actionContext = new ActionContext(httpContext, new RouteData(), new ActionDescriptor());
            using (var sw = new StringWriter())
            {
                var viewResult = _razorViewEngine.FindView(actionContext, viewName, false);
               
                if (viewResult.View == null)
                {
                    throw new ArgumentNullException($"{viewName} does not match any available view");
                }

                var viewDictionary = new ViewDataDictionary(new EmptyModelMetadataProvider(), new ModelStateDictionary())
                {
                    Model = model
                };

                var viewContext = new ViewContext(
                    actionContext,
                    viewResult.View,
                    viewDictionary,
                    new TempDataDictionary(actionContext.HttpContext, _tempDataProvider),
                    sw,
                    new HtmlHelperOptions()
                );

                await viewResult.View.RenderAsync(viewContext);
                return sw.ToString();
            }
        }
    }
}

HomeController

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;
using AssemblyPartLIb;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using WebApplication8.Models;

namespace WebApplication8.Controllers
{
    public class HomeController : Controller
    {
        private readonly ILogger _logger;
        private readonly IViewRenderService _viewRenderService;
        public HomeController(ILogger logger, IViewRenderService viewRenderService)
        {
            _logger = logger;
            _viewRenderService = viewRenderService;
        }

        public async Task Index()
        {
            var html =await _viewRenderService.RenderViewToStringAsync("Home/Index", new { });
            return View();
        }

     
    }
}