c# - RazorEngine 字符串布局和部分？

Question

我像这样使用 Razor 引擎:

public class EmailService : IService
{
    private readonly ITemplateService templateService;

    public EmailService(ITemplateService templateService)
    {
        if (templateService == null)
        {
            throw new ArgumentNullException("templateService");
        }
        this.templateService = templateService;
    }

    public string GetEmailTemplate(string templateName)
    {
        if (templateName == null)
        {
            throw new ArgumentNullException("templateName");
        }
        Assembly assembly = Assembly.GetAssembly(typeof(EmailTemplate));
        Stream stream = assembly.GetManifestResourceStream(typeof(EmailTemplate), "{0}.cshtml".FormatWith(templateName));
        string template = stream.ReadFully();
        return template;
    }

    public string GetEmailBody(string templateName, object model = null)
    {
        if (templateName == null)
        {
            throw new ArgumentNullException("templateName");
        }
        string template = GetEmailTemplate(templateName);
        string emailBody = templateService.Parse(template, model, null, null);
        return emailBody;
    }
}

我使用的模板服务是注入(inject)的，尽管它只是一个默认实现:

    internal ITemplateService InstanceDefaultTemplateService()
    {
        ITemplateServiceConfiguration configuration = new TemplateServiceConfiguration();
        ITemplateService service = new TemplateService(configuration);
        return service;
    }

特别是在这种情况下，我将从这些模板构建电子邮件。我希望能够将 @section 用于电子邮件的主题和电子邮件正文的不同部分，同时使用我指定整个电子邮件结构通用样式的布局(这可能看起来像 MailChimp 之一)。

那么问题是双重的:

• 如何在 RazorEngine 中指定布局？
• 如何从字符串(或流)中指定这些布局？因为如您所见，我使用嵌入式资源来存储 Razor 电子邮件模板。

更新

也许我不清楚，但我指的是 RazorEngine图书馆。

Answer 1

经过一些挖掘后发现支持布局，我们只需要用 _Layout 而不是 Layout 声明它们

关于嵌入资源的问题，我实现了如下ITemplateResolver

using System;
using System.IO;
using System.Reflection;
using Bruttissimo.Common;
using RazorEngine.Templating;

namespace Website.Extensions.RazorEngine
{
    /// <summary>
    /// Resolves templates embedded as resources in a target assembly.
    /// </summary>
    public class EmbeddedTemplateResolver : ITemplateResolver
    {
        private readonly Assembly assembly;
        private readonly Type type;
        private readonly string templateNamespace;

        /// <summary>
        /// Specify an assembly and the template namespace manually.
        /// </summary>
        /// <param name="assembly">The assembly where the templates are embedded.</param>
        /// <param name="templateNamespace"></param>
        public EmbeddedTemplateResolver(Assembly assembly, string templateNamespace)
        {
            if (assembly == null)
            {
                throw new ArgumentNullException("assembly");
            }
            if (templateNamespace == null)
            {
                throw new ArgumentNullException("templateNamespace");
            }
            this.assembly = assembly;
            this.templateNamespace = templateNamespace;
        }

        /// <summary>
        /// Uses a type reference to resolve the assembly and namespace where the template resources are embedded.
        /// </summary>
        /// <param name="type">The type whose namespace is used to scope the manifest resource name.</param>
        public EmbeddedTemplateResolver(Type type)
        {
            if (type == null)
            {
                throw new ArgumentNullException("type");
            }
            this.assembly = Assembly.GetAssembly(type);
            this.type = type;
        }

        public string Resolve(string name)
        {
            if (name == null)
            {
                throw new ArgumentNullException("name");
            }
            Stream stream;
            if (templateNamespace == null)
            {
                stream = assembly.GetManifestResourceStream(type, "{0}.cshtml".FormatWith(name));
            }
            else
            {
                stream = assembly.GetManifestResourceStream("{0}.{1}.cshtml".FormatWith(templateNamespace, name));
            }
            if (stream == null)
            {
                throw new ArgumentException("EmbeddedResourceNotFound");
            }
            string template = stream.ReadFully();
            return template;
        }
    }
}

然后你只需像这样连接它:

    internal static ITemplateService InstanceTemplateService()
    {
        TemplateServiceConfiguration configuration = new TemplateServiceConfiguration
        {
            Resolver = new EmbeddedTemplateResolver(typeof(EmailTemplate))
        };
        ITemplateService service = new TemplateService(configuration);
        return service;
    }

您传递的类型仅用于引用嵌入资源的程序集和命名空间。

namespace Website.Domain.Logic.Email.Template
{
    /// <summary>
    /// The purpose of this class is to expose the namespace of razor engine templates in order to
    /// avoid having to hard-code it when retrieving the templates embedded as resources.
    /// </summary>
    public sealed class EmailTemplate
    {
    }
}

最后一件事，为了让我们的解析器解析模板，我们必须像这样解析它们:

ITemplate template = templateService.Resolve(templateName, model);
string body = template.Run();
return body;

.Run 只是一个简单的扩展方法，因为我找不到 ViewBag 的任何用途。

public static class ITemplateExtensions
{
    public static string Run(this ITemplate template)
    {
        ExecuteContext context = new ExecuteContext();
        string result = template.Run(context);
        return result;
    }
}

更新

这是缺少的扩展

    public static string FormatWith(this string text, params object[] args)
    {
        return string.Format(text, args);
    }

    public static string ReadFully(this Stream stream)
    {
        using (StreamReader reader = new StreamReader(stream))
        {
            return reader.ReadToEnd();
        }
    }