在ASP中将Razor视图渲染为字符串.净的核心

本文关键字：字符串 核心 ASP 中将 Razor 视图 | 更新日期: 2023-09-27 18:12:40

我使用RazorEngine在我的MVC 6项目中解析模板，如下所示:

Engine.Razor.RunCompile(File.ReadAllText(fullTemplateFilePath), templateName, null, model);

它在beta 6中工作得很好。升级到beta 7后无法工作，错误如下:

MissingMethodException: Method not found: "Void microsoft.aspnet . razor . codegenerator . generatedclasscontext . set_resolveurlmethodname (System.String)"。在RazorEngine.Compilation.CompilerServiceBase。CreateHost(Type templateType, Type modelType, String className)

This is global.json:

{
  "projects": [ "src", "test" ],
  "sdk": {
    "version": "1.0.0-beta7",
    "runtime": "clr",
    "architecture": "x64"
  }
}

这是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>

有人有类似的问题吗?有另一种方法来解析模板在MVC 6?

在ASP中将Razor视图渲染为字符串.净的核心

更新7月,2016年

在以下版本1.0.0, RC2上运行良好

谁的目标是aspnetcore RC2，这个片段可能会帮助你:

  • 创建一个单独的Service，这样你就可以使用它，如果你不是在一个控制器上下文中，例如从命令行或队列运行器，等等…
  • 在Startup类的IoC容器中注册此服务
https://gist.github.com/ahmad-moussawi/1643d703c11699a6a4046e57247b4d09

使用

// 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);
指出

Razor中的链接呈现为相对 URL，因此这将无法在外部视图(如电子邮件等)上工作。

到目前为止，我在控制器上生成链接，并通过ViewModel将其传递给视图。

信贷

来源是提取自(感谢@pholly): https://github.com/aspnet/Entropy/blob/dev/samples/Mvc.RenderViewToString/RazorViewToStringRenderer.cs)

我发现这个线程讨论它:https://github.com/aspnet/Mvc/issues/3091

有人在线程中创建了一个示例服务:https://github.com/aspnet/Entropy/blob/dev/samples/Mvc.RenderViewToString/RazorViewToStringRenderer.cs

经过反复试验，我能够削减服务，所以它只需要一个有效的HttpContext和ViewEngine，我添加了一个不需要模型的过载。视图是相对于你的应用程序根目录的(它们不必存在于Views文件夹中)。

您需要在Startup.cs和HttpContextAccessor中注册服务:

//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();
            }
        }
    }
}

使用例子:

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;
        }
    }
}

在过去，我在类库中使用RazorEngine，因为我的目标是从这个类库中呈现模板。

从我的理解，你似乎是在MVC 6.0项目内，所以为什么不使用RenderPartialViewToString()方法，而不必添加对RazorEngine的依赖?

请记住，我问这个只是因为我很好奇。

例如，在VS2015中，我创建了一个新的ASP。. NET Web应用程序，并从ASP. NET中选择Web应用程序模板。. NET 5预览模板。

在ViewModels文件夹中，我创建了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);
        }
    } 
}

然后我创建了一个新的BaseController，并添加了一个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();
    }
}

感谢@DavidG的方法

在Views-->Shared文件夹中，我创建了一个新的模板文件夹，在其中我添加了一个简单的RegistrationTemplate.cshtml视图强类型到我的PersonViewModel，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>

最后一步是让我的Controller继承我的BaseController 

public class MyController : BaseController

并创建如下内容:

public IActionResult Index()
{
    var model = new PersonViewModel();
    model.FirstName = "Frank";
    model.LastName = "Underwood";
    var emailbody = base.RenderPartialViewToString("Templates/RegistrationTemplate", model);
    return View();
}

当然，上面的例子是无用的，因为我没有对变量emailbody做任何操作，但是我的想法是展示它是如何使用的。

此时，我可以(例如)调用EmailService并传递emailbody:

_emailService.SendEmailAsync("test@test.com", "registration", emailbody);

我不确定这是否适合你目前的任务。

今天我已经完成了我的库，可以解决你的问题。你可以在ASP中使用它。. NET，因为它不依赖于它

的例子:

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

为了改进@ vince答案(这对我来说不是开箱即用的)，以下是我所做的:

1-创建一个基本控制器，你的其他控制器将继承

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-继承基本控制器并调用方法

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);
        }
    }
}

ResolveUrlMethodName被删除。因此，在您的CreateHost这里，您试图设置一个不存在的属性:)。

我们决定将~/处理从核心Razor移动到Microsoft.AspNet.Mvc.Razor组件中实现的TagHelper。这是提交到删除方法的位。

希望这有帮助。

将部分视图转换为字符串响应的扩展方法。

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();
        }
    }
}

在你的控制器动作中的用法

public async Task<IActionResult> Index()
{
    return await PartialView().ToString(ControllerContext)
}

。. NET 5实现

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();
        }
    }

仅使用ASP的另一种解决方案。. NET Core，没有外部库，也没有反射可以在这里找到:https://weblogs.asp.net/ricardoperes/getting-html-for-a-viewresult-in-asp-net-core。只需要一个ViewResult和一个HttpContext。

这个想法是拿起一个ViewResult并调用一些方法，比如ToHtml，来获得渲染的输出。这个方法看起来像这样:

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();
    }
}

使用它，只需:

var view = this.View(“ViewName”);
var html = view.ToHtml();
相关文章：