邮件的内容其实是就HTML,传统的做法都是通过在程序中拼接字符串来生成邮件的内容,生成困难,维护也困难。Razor是MVC里面使用的视图引擎,用来生成HTML非常方便,ZKEACMS中就是使用了Razor视图引擎,用cshtml作为邮件模板来生成邮件内容。这样很方便维护和修改。

定义接口 IViewRenderService

接口中定义了两个方法,第一个是视图中没有使用ViewModel,直接传入视图路径就可以了。第二个是视图中有作用ViewModel,传入视图路径和ViewModel对象就可以。

namespace Easy.Mvc.RazorPages
{
    public interface IViewRenderService
    {
        string Render(string viewPath);
        string Render<Model>(string viewPath, Model model);
    }
}

接口实现 ViewRenderService

实现的方式也比较简单,主要还是直接使用了RazorViewEngine:

namespace Easy.Mvc.RazorPages
{
    public class ViewRenderService : IViewRenderService
    {
        private readonly IRazorViewEngine _viewEngine;
        private readonly ITempDataProvider _tempDataProvider;
        private readonly IServiceProvider _serviceProvider;

        public ViewRenderService(IRazorViewEngine viewEngine, ITempDataProvider tempDataProvider,
            IServiceProvider serviceProvider)
        {
            _viewEngine = viewEngine;
            _tempDataProvider = tempDataProvider;
            _serviceProvider = serviceProvider;
        }
        public string Render(string viewPath)
        {
            return Render(viewPath, string.Empty);
        }
        public string Render<TModel>(string viewPath, TModel model)
        {
            var httpContext = new DefaultHttpContext { RequestServices = _serviceProvider };
            var actionContext = new ActionContext(httpContext, new RouteData(), new ActionDescriptor());

            var viewResult = _viewEngine.GetView(null, viewPath, false);
            if (!viewResult.Success)
            {
                throw new InvalidOperationException($"找不到视图模板 {viewPath}");
            }

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

            using (var writer = new StringWriter())
            {
                var viewContext = new ViewContext(
                     actionContext,
                     viewResult.View,
                     viewDictionary,
                     new TempDataDictionary(actionContext.HttpContext, _tempDataProvider),
                     writer,
                     new HtmlHelperOptions()
                 );
                var render = viewResult.View.RenderAsync(viewContext);
                render.Wait();
                return writer.ToString();
            }
        }
    }
}

使用

使用的方法也很简单,首先要先建一个邮件模板,例如 ResetPassword.cshtml

代码如下:

@model ZKEACMS.Notification.ViewModels.ResetPasswordViewModel
<!DOCTYPE html>
<html class="not-ie" lang="zh">
<head>
<title>重置密码</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta charset="utf-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
</head>
<body>
<h3>
您正在重置密码,
</h3>
<p>
您可以使用以下链接来重置您的密码,为了安全,该链接仅会在一段时间内有效,请尽快重置密码
</p>
<p>
<a href="@Model.Link">
@Model.Link
</a>
</p>
<h4>
ZKEASOFT
</h4>
<p>
<a href="http://www.zkea.net">
http://www.zkea.net
</a>
</p>
<p>
<em>@DateTime.Now.ToString("yyyy-MM-dd")</em>
</p>
</body>
</html>

接下来就是调用ViewRenderService

 var htmlContent = _viewRenderService.Render("~/EmailTemplates/ResetPassword.cshtml", new ResetPasswordViewModel{Link=...});

有了内容以后,就可以直接调用发送了。