在ASP.NET MVC 5中從數據庫加載Razor視圖

Question

我們正在嘗試在ASP.NET MVC 5中開發企業CMS應用程序。用戶需要創建新頁面，更改現有頁面內容或從管理應用程序中完全刪除頁面。 另一個要求是，某些頁面可以包含使用Razor語法編寫的自定義小部件。

這兩個要求使我從數據庫加載剃刀視圖。 我用Google搜索並找到了幾個例子。

第一個是擴展VirtualPathProvider並在Application_Start方法中使用下面的表達式注冊它。

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

當我嘗試運行它時，它會拋出下面的錯誤

[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

另一個例子是

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

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

當指定的文件（例如/View/Home/Index.cshtml）在文件系統中時，即使它沒有任何內容，也可以使用此文件。 當我從文件系統中刪除文件時，會拋出以下錯誤

[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

即使您重寫VirtualPathProvider以從數據庫加載視圖數據，RazorViewEngine也會嘗試在文件系統中查找該文件。

我想這些例子在以前版本的ASP.NET MVC中工作（我認為2或3）。 我得到的最好的解決方案是從頭開始編寫自定義視圖引擎，但是要做的工作太多，以使其像剃刀視圖引擎一樣工作。 有沒有其他技巧可以使這些示例有效，或者其他任何替代方案？

Answer 1

看看這些鏈接。 希望這可能有所幫助。

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

使用自定義VirtualPathProvider加載嵌入式資源部分視圖

在數據庫中存儲ASP.Net MVC視圖

ASP.NET MVC從數據庫加載Razor視圖