[英]Render Razor View to string in ASP.NET Core
我使用RazorEngine在我的 MVC 6 項目中解析模板，如下所示：
Engine.Razor.RunCompile(File.ReadAllText(fullTemplateFilePath), templateName, null, model);
它適用於 beta 6。升級到 beta 7 后它無法正常工作，並出現以下錯誤：
MissingMethodException：找不到方法：“無效 Microsoft.AspNet.Razor.CodeGenerators.GeneratedClassContext.set_ResolveUrlMethodName(System.String)”。 在 RazorEngine.Compilation.CompilerServiceBase.CreateHost（類型模板類型，類型模型類型，字符串類名）
這是 global.json：
{
"projects": [ "src", "test" ],
"sdk": {
"version": "1.0.0-beta7",
"runtime": "clr",
"architecture": "x64"
}
}
這是project.json：
...
"dependencies": {
"EntityFramework.SqlServer": "7.0.0-beta7",
"EntityFramework.Commands": "7.0.0-beta7",
"Microsoft.AspNet.Mvc": "6.0.0-beta7",
"Microsoft.AspNet.Mvc.TagHelpers": "6.0.0-beta7",
"Microsoft.AspNet.Authentication.Cookies": "1.0.0-beta7",
"Microsoft.AspNet.Authentication.Facebook": "1.0.0-beta7",
"Microsoft.AspNet.Authentication.Google": "1.0.0-beta7",
"Microsoft.AspNet.Authentication.MicrosoftAccount": "1.0.0-beta7",
"Microsoft.AspNet.Authentication.Twitter": "1.0.0-beta7",
"Microsoft.AspNet.Diagnostics": "1.0.0-beta7",
"Microsoft.AspNet.Diagnostics.Entity": "7.0.0-beta7",
"Microsoft.AspNet.Identity.EntityFramework": "3.0.0-beta7",
"Microsoft.AspNet.Server.IIS": "1.0.0-beta7",
"Microsoft.AspNet.Server.WebListener": "1.0.0-beta7",
"Microsoft.AspNet.StaticFiles": "1.0.0-beta7",
"Microsoft.AspNet.Tooling.Razor": "1.0.0-beta7",
"Microsoft.Framework.Configuration.Abstractions": "1.0.0-beta7",
"Microsoft.Framework.Configuration.Json": "1.0.0-beta7",
"Microsoft.Framework.Configuration.UserSecrets": "1.0.0-beta7",
"Microsoft.Framework.Logging": "1.0.0-beta7",
"Microsoft.Framework.Logging.Console": "1.0.0-beta7",
"Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0-beta7",
"RazorEngine": "4.2.2-beta1"
},
...
"frameworks": {
"dnx451": { }
},
...
我的模板是：
@model dynamic @{ Layout = null; } <!DOCTYPE html> <html lang="en" xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8" /> <title>Registration</title> </head> <body> <p> Hello, @Model </p> </body> </html>
有沒有人有類似的問題？ 在 MVC 6 中還有另一種解析模板的方法嗎？
在以下版本1.0.0 , RC2上工作正常
誰以 aspnetcore RC2 為目標，此代碼段可能對您有所幫助：
Startup類的 IoC 容器中注冊此服務https://gist.github.com/ahmad-moussawi/1643d703c11699a6a4046e57247b4d09
// using a Model
string html = view.Render("Emails/Test", new Product("Apple"));
// using a Dictionary<string, object>
var viewData = new Dictionary<string, object>();
viewData["Name"] = "123456";
string html = view.Render("Emails/Test", viewData);
Razor 中的鏈接呈現為相對URL，因此這不適用於外部視圖（如電子郵件等）。
至於現在在控制器上生成鏈接並通過 ViewModel 將其傳遞給視圖。
源代碼摘自（感謝@pholly）： https ://github.com/aspnet/Entropy/blob/dev/samples/Mvc.RenderViewToString/RazorViewToStringRenderer.cs）
我發現這個討論它的線程： https ://github.com/aspnet/Mvc/issues/3091
線程中的某個人在這里創建了一個示例服務： https ://github.com/aspnet/Entropy/blob/dev/samples/Mvc.RenderViewToString/RazorViewToStringRenderer.cs
經過反復試驗，我能夠減少服務，因此它只需要一個有效的HttpContext和一個ViewEngine並且我添加了一個不需要模型的重載。 視圖相對於您的應用程序根目錄（它們不必位於Views文件夾中）。
您需要在Startup.cs中注冊服務並注冊HttpContextAccessor ：
//Startup.cs ConfigureServices()
services.AddTransient<ViewRenderService>();
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.Razor;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using System;
using System.IO;
namespace LibraryApi.Services
{
public class ViewRenderService
{
IRazorViewEngine _viewEngine;
IHttpContextAccessor _httpContextAccessor;
public ViewRenderService(IRazorViewEngine viewEngine, IHttpContextAccessor httpContextAccessor)
{
_viewEngine = viewEngine;
_httpContextAccessor = httpContextAccessor;
}
public string Render(string viewPath)
{
return Render(viewPath, string.Empty);
}
public string Render<TModel>(string viewPath, TModel model)
{
var viewEngineResult = _viewEngine.GetView("~/", viewPath, false);
if (!viewEngineResult.Success)
{
throw new InvalidOperationException($"Couldn't find view {viewPath}");
}
var view = viewEngineResult.View;
using (var output = new StringWriter())
{
var viewContext = new ViewContext();
viewContext.HttpContext = _httpContextAccessor.HttpContext;
viewContext.ViewData = new ViewDataDictionary<TModel>(new EmptyModelMetadataProvider(), new ModelStateDictionary())
{ Model = model };
viewContext.Writer = output;
view.RenderAsync(viewContext).GetAwaiter().GetResult();
return output.ToString();
}
}
}
}
示例用法：
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using LibraryApi.Services;
using System.Dynamic;
namespace LibraryApi.Controllers
{
[Route("api/[controller]")]
public class ValuesController : Controller
{
ILogger<ValuesController> _logger;
ViewRenderService _viewRender;
public ValuesController(ILogger<ValuesController> logger, ViewRenderService viewRender)
{
_logger = logger;
_viewRender = viewRender;
}
// GET api/values
[HttpGet]
public string Get()
{
//ViewModel is of type dynamic - just for testing
dynamic x = new ExpandoObject();
x.Test = "Yes";
var viewWithViewModel = _viewRender.Render("eNotify/Confirm.cshtml", x);
var viewWithoutViewModel = _viewRender.Render("MyFeature/Test.cshtml");
return viewWithViewModel + viewWithoutViewModel;
}
}
}
過去，我在類庫中使用過RazorEngine ，因為我的目標是在這個類庫中呈現模板。
據我了解，您似乎在 MVC 6.0 項目中，所以為什么不使用RenderPartialViewToString()方法而不必添加對RazorEngine的依賴項？
請記住，我只是問，因為我很好奇。
例如，在 VS2015 中，我創建了一個新的 ASP.NET Web 應用程序，並從 ASP.NET 5 Preview Templates 中選擇了 Web Application 模板。
在ViewModels文件夾中，我創建了一個PersonViewModel ：
public class PersonViewModel
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string FullName
{
get
{
return string.Format("{0} {1}", this.FirstName, this.LastName);
}
}
}
然后我創建了一個新的BaseController並添加了一個RenderPartialViewToString()方法：
public string RenderPartialViewToString(string viewName, object model)
{
if (string.IsNullOrEmpty(viewName))
viewName = ActionContext.ActionDescriptor.Name;
ViewData.Model = model;
using (StringWriter sw = new StringWriter())
{
var engine = Resolver.GetService(typeof(ICompositeViewEngine)) as ICompositeViewEngine;
ViewEngineResult viewResult = engine.FindPartialView(ActionContext, viewName);
ViewContext viewContext = new ViewContext(ActionContext, viewResult.View, ViewData, TempData, sw,new HtmlHelperOptions());
var t = viewResult.View.RenderAsync(viewContext);
t.Wait();
return sw.GetStringBuilder().ToString();
}
}
歸功於@DavidG 他的方法
在Views-->Shared文件夾中，我創建了一個新的Templates文件夾，我在其中添加了一個簡單的RegistrationTemplate.cshtml視圖，該視圖強類型化到我的PersonViewModel中，如下所示：
@model MyWebProject.ViewModels.PersonViewModel
<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title>Registration</title>
</head>
<body>
<p>
Hello, @Model.FullName
</p>
</body>
</html>
最后一步是讓我的Controller繼承自我的BaseController
public class MyController : BaseController
並創建類似：
public IActionResult Index()
{
var model = new PersonViewModel();
model.FirstName = "Frank";
model.LastName = "Underwood";
var emailbody = base.RenderPartialViewToString("Templates/RegistrationTemplate", model);
return View();
}
當然，上面的例子是沒有用的，因為我沒有對變量emailbody做任何事情，但我的想法是展示它是如何使用的。
此時，我可以（例如）調用EmailService並傳遞emailbody ：
_emailService.SendEmailAsync("test@test.com", "registration", emailbody);
我不確定這是否適合您當前的任務。
今天我已經完成了可以解決您問題的庫。 您可以在 ASP.NET 之外使用它，因為它不依賴於它
例子：
string content = "Hello @Model.Name. Welcome to @Model.Title repository";
var model = new
{
Name = "John Doe",
Title = "RazorLight"
};
var engine = new RazorLightEngine();
string result = engine.ParseString(content, model);
//Output: Hello John Doe, Welcome to RazorLight repository
更多： https ://github.com/toddams/RazorLight
為了改進@vlince的答案（這對我來說不是開箱即用的），這就是我所做的：
1-創建一個您的其他控制器將繼承的基本控制器
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.ViewEngines;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Mvc.Rendering;
using System.IO;
namespace YourNameSpace
{
public class BaseController : Controller
{
protected ICompositeViewEngine viewEngine;
public BaseController(ICompositeViewEngine viewEngine)
{
this.viewEngine = viewEngine;
}
protected string RenderViewAsString(object model, string viewName = null)
{
viewName = viewName ?? ControllerContext.ActionDescriptor.ActionName;
ViewData.Model = model;
using (StringWriter sw = new StringWriter())
{
IView view = viewEngine.FindView(ControllerContext, viewName, true).View;
ViewContext viewContext = new ViewContext(ControllerContext, view, ViewData, TempData, sw, new HtmlHelperOptions());
view.RenderAsync(viewContext).Wait();
return sw.GetStringBuilder().ToString();
}
}
}
}
2-繼承基本控制器並調用方法
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.ViewEngines;
namespace YourNameSpace
{
public class YourController : BaseController
{
public YourController(ICompositeViewEngine viewEngine) : base(viewEngine) { }
public string Index(int? id)
{
var model = new MyModel { Name = "My Name" };
return RenderViewAsString(model);
}
}
}
將部分視圖轉換為字符串響應的擴展方法。
public static class PartialViewToString
{
public static async Task<string> ToString(this PartialViewResult partialView, ActionContext actionContext)
{
using(var writer = new StringWriter())
{
var services = actionContext.HttpContext.RequestServices;
var executor = services.GetRequiredService<PartialViewResultExecutor>();
var view = executor.FindView(actionContext, partialView).View;
var viewContext = new ViewContext(actionContext, view, partialView.ViewData, partialView.TempData, writer, new HtmlHelperOptions());
await view.RenderAsync(viewContext);
return writer.ToString();
}
}
}
在您的控制器操作中使用。
public async Task<IActionResult> Index()
{
return await PartialView().ToString(ControllerContext)
}
.NET 5 實施
public static async Task<string> ViewToString(this PartialViewResult partialView, Controller controller)
{
using (var writer = new StringWriter())
{
var services = controller.ControllerContext.HttpContext.RequestServices;
var viewEngine = services.GetService(typeof(ICompositeViewEngine)) as ICompositeViewEngine;
var viewName = partialView.ViewName ?? controller.ControllerContext.ActionDescriptor.ActionName;
var view = viewEngine.FindView(controller.ControllerContext, viewName, false).View;
var viewContext = new ViewContext(controller.ControllerContext, view, partialView.ViewData, partialView.TempData, writer, new HtmlHelperOptions());
await view.RenderAsync(viewContext);
return writer.ToString();
}
}
可以在此處找到僅使用 ASP.NET Core、沒有外部庫和反射的替代解決方案： https ://weblogs.asp.net/ricardoperes/getting-html-for-a-viewresult-in-asp-net- 核心。 它只需要一個ViewResult和一個HttpContext 。
這個想法是獲取一個ViewResult並調用一些方法，比如ToHtml ，以獲取渲染的輸出。 此方法可能如下所示：
public static class ViewResultExtensions {
public static string ToHtml(this ViewResult result, HttpContext httpContext) {
var feature = httpContext.Features.Get<IRoutingFeature>();
var routeData = feature.RouteData;
var viewName = result.ViewName ?? routeData.Values["action"] as string;
var actionContext = new ActionContext(httpContext, routeData, new ControllerActionDescriptor());
var options = httpContext.RequestServices.GetRequiredService<IOptions<MvcViewOptions>>();
var htmlHelperOptions = options.Value.HtmlHelperOptions;
var viewEngineResult = result.ViewEngine?.FindView(actionContext, viewName, true) ?? options.Value.ViewEngines.Select(x => x.FindView(actionContext, viewName, true)).FirstOrDefault(x => x != null);
var view = viewEngineResult.View;
var builder = new StringBuilder();
using (var output = new StringWriter(builder)) {
var viewContext = new ViewContext(actionContext, view, result.ViewData, result.TempData, output, htmlHelperOptions);
view
.RenderAsync(viewContext)
.GetAwaiter()
.GetResult();
}
return builder.ToString();
}
}
要使用它，只需執行以下操作：
var view = this.View(“ViewName”);
var html = view.ToHtml();
ASP.NET CORE 將 Razor 視圖渲染為帶有控制器參數的字符串
[英]ASP.NET CORE Render Razor View to string with controller parameters
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