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从ASP.NET MVC中的数据库加载Razor视图5

分类: 技术问答 • 2022-06-09 12:31:25
问题描述：

我们正在尝试在ASP.NET MVC 5中开发一个企业CMS应用程序。用户需要创建一个新页面，更改现有页面内容或从中删除一个页面管理员应用程序。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。从ASP.NET MVC中的数据库加载Razor视图5

这2个要求导致我从数据库加载剃须刀视图。我搜索了一下，找到了几个例子。

第一个是扩展VirtualPathProvider，并在Application_Start方法中将其注册为下面的表达式。

protected void Application_Start() 
{ 
    ... 
    HostingEnvironment.RegisterVirtualPathProvider(new MyVirtualPathProvider()); 
}

当我尝试运行它，它会引发以下

 
[InvalidOperationException: The view at '~/Views/Home/Index.aspx' must derive from ViewPage, ViewPage, ViewUserControl, or 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 context) +291 
    System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +13 
    System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +56 
    System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +420 
    System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, 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, Controller controller) +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 result) +9 
    System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9644097 
    System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

错误另一个例子是

protected void Application_Start() 
{ 
    ... 
    ViewEngines.Engines.Clear(); 
    ViewEngines.Engines.Add(new MyViewEngine()); 
} 

private class MyViewEngine : RazorViewEngine 
{ 
    public MyViewEngine() 
    { 
     this.VirtualPathProvider = new MyVirtualPathProvider(); 
    } 
}

这一个工程时，指定的文件（如/浏览/首页/ Index.cshtml）在文件系统中，即使它没有任何内容。当我从文件系统删除文件，下面的错误被抛出

 
[InvalidOperationException: The view 'Index' or its master was not found or no view engine supports the searched locations. The following locations were searched: 
    ~/Views/Home/Index.cshtml 
    ~/Views/Home/Index.vbhtml 
    ~/Views/Shared/Index.cshtml 
    ~/Views/Shared/Index.vbhtml] 
    System.Web.Mvc.ViewResult.FindView(ControllerContext context) +382 
    System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +116 
    System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +13 
    System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +56 
    System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +420 
    System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, 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, Controller controller) +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 result) +9 
    System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9644097 
    System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

的RazorViewEngine试图找到，即使你覆盖的VirtualPathProvider从数据库加载视图数据的文件系统中的文件。

我想这些例子在ASP.NET MVC的早期版本中工作（我认为2或3）。我得到的最佳解决方案是从零开始编写自定义视图引擎，但要完成像剃须刀视图引擎一样的工作还有很多工作要做。有没有其他技巧可以让这些例子起作用，或者有其他的选择吗？

答

看看这些链接。希望这可能有所帮助。

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

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