在 ASP.NET MVC 5 中从数据库加载 Razor 视图

Posted 2023-03-30

【中文标题】在 ASP.NET MVC 5 中从数据库加载 Razor 视图

【英文标题】：Load Razor Views From Database in ASP.NET MVC 5

【发布时间】：2016-11-25 08:10:15

【问题描述】：

我们正在尝试在 ASP.NET MVC 5 中开发企业 CMS 应用程序。用户需要从管理应用程序中创建新页面、更改现有页面内容或删除页面。另一个要求是某些页面可以包含用 Razor 语法编写的自定义小部件。

这两个要求导致我从数据库加载剃刀视图。我用谷歌搜索并找到了几个例子。

第一个是扩展 VirtualPathProvider 并在 Application_Start 方法中使用下面的表达式注册它。

protected void Application_Start()

    ...
    HostingEnvironment.RegisterVirtualPathProvider(new MyVirtualPathProvider());

当我尝试运行它时，它会抛出下面的错误

[InvalidOperationException：'~/Views/Home/Index.aspx' 处的视图必须派生自 ViewPage、ViewPage、ViewUserControl 或 ViewUserControl。] System.Web.Mvc.WebFormView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) +180 System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) +107 System.Web.Mvc.ViewResultBase.ExecuteResult（ControllerContext 上下文）+291 System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +13 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive（IList`1 过滤器，Int32 filterIndex，ResultExecutingContext preContext，ControllerContext controllerContext，ActionResult actionResult）+56 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive（IList`1 过滤器，Int32 filterIndex，ResultExecutingContext preContext，ControllerContext controllerContext，ActionResult actionResult）+420 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 过滤器, ActionResult actionResult) +52 System.Web.Mvc.Async.c__DisplayClass2b.b__1c() +173 System.Web.Mvc.Async.c__DisplayClass21.b__1e(IAsyncResult asyncResult) +100 System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10 System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49 System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27 System.Web.Mvc.Controller.b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +13 System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29 System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49 System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +36 System.Web.Mvc.Controller.b__15（IAsyncResult asyncResult，控制器控制器）+12 System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +22 System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49 System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26 System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10 System.Web.Mvc.MvcHandler.b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +21 System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29 System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49 System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult 结果) +9 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9644097 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

另一个例子是

protected void Application_Start()

    ...
    ViewEngines.Engines.Clear();
    ViewEngines.Engines.Add(new MyViewEngine());


private class MyViewEngine : RazorViewEngine

    public MyViewEngine()
    
        this.VirtualPathProvider = new MyVirtualPathProvider();
    

当指定的文件（例如 /View/Home/Index.cshtml）在文件系统中时，即使它没有任何内容，这个也可以工作。当我从文件系统中删除文件时，抛出以下错误

[InvalidOperationException：未找到视图“索引”或其主视图，或者没有视图引擎支持搜索的位置。搜索了以下位置： ~/Views/Home/Index.cshtml ~/Views/Home/Index.vbhtml ~/Views/Shared/Index.cshtml ~/Views/Shared/Index.vbhtml] System.Web.Mvc.ViewResult.FindView（ControllerContext 上下文）+382 System.Web.Mvc.ViewResultBase.ExecuteResult（ControllerContext 上下文）+116 System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +13 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive（IList`1 过滤器，Int32 filterIndex，ResultExecutingContext preContext，ControllerContext controllerContext，ActionResult actionResult）+56 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive（IList`1 过滤器，Int32 filterIndex，ResultExecutingContext preContext，ControllerContext controllerContext，ActionResult actionResult）+420 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 过滤器, ActionResult actionResult) +52 System.Web.Mvc.Async.c__DisplayClass2b.b__1c() +173 System.Web.Mvc.Async.c__DisplayClass21.b__1e(IAsyncResult asyncResult) +100 System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10 System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49 System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27 System.Web.Mvc.Controller.b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +13 System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29 System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49 System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +36 System.Web.Mvc.Controller.b__15（IAsyncResult asyncResult，控制器控制器）+12 System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +22 System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49 System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26 System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10 System.Web.Mvc.MvcHandler.b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +21 System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29 System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49 System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult 结果) +9 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9644097 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

即使您覆盖 VirtualPathProvider 以从数据库加载视图数据，RazorViewEngine 也会尝试在文件系统中查找文件。

我猜这些示例适用于以前版本的 ASP.NET MVC（我认为是 2 或 3）。我得到的最好的解决方案是从头开始编写一个自定义视图引擎，但是要让它像剃刀视图引擎一样工作还有很多工作要做。是否有任何其他技巧可以使这些示例正常工作，或者任何其他替代方法？

【参考方案1】：

看看这些链接。希望这可能会有所帮助。

http://rebuildall.umbraworks.net/2009/11/17/ASP_NET_MVC_and_virtual_views

Using custom VirtualPathProvider to load embedded resource Partial Views

Storing ASP.Net MVC Views in the Database

ASP.NET MVC load Razor view from database