对于我的项目，我目前为我的 asp.net core 应用程序实现了 ViewRender。它生成没有控制器的 html 视图，使用以下代码可以正常工作：
public class ViewRenderService : IViewRenderService
{
private readonly IRazorViewEngine _razorViewEngine;
private readonly ITempDataProvider _tempDataProvider;
private readonly IServiceProvider _serviceProvider;
public ViewRenderService(IRazorViewEngine razorViewEngine,
ITempDataProvider tempDataProvider,
IServiceProvider serviceProvider)
{
_razorViewEngine = razorViewEngine;
_tempDataProvider = tempDataProvider;
_serviceProvider = serviceProvider;
}
public async Task<string> RenderToStringAsync(string viewName, object model)
{
var httpContext = new DefaultHttpContext { RequestServices = _serviceProvider };
var actionContext = new ActionContext(httpContext, new RouteData(), new ActionDescriptor());
string viewgerendered = "";
try
{
using (var sw = new StringWriter())
{
var viewResult = _razorViewEngine.GetView(viewName, viewName, false);
if (viewResult.View == null)
{
throw new ArgumentNullException($"{viewName} does not match any available view");
}
var viewDictionary = new ViewDataDictionary(new EmptyModelMetadataProvider(), new ModelStateDictionary())
{
Model = model
};
var viewContext = new ViewContext(
actionContext,
viewResult.View,
viewDictionary,
new TempDataDictionary(actionContext.HttpContext, _tempDataProvider),
sw,
new HtmlHelperOptions()
);
await viewResult.View.RenderAsync(viewContext);
viewgerendered = sw.ToString();
return viewgerendered;
}
}
catch (Exception e)
{
object temp = e.Message + " - " + e.StackTrace;
return temp.ToString();
}
}
public Task RenderToStringAsync(string v)
{
throw new NotImplementedException();
}
}
来源：https://ppolyzos.com/2016/09/09/asp-net-core-render-view-to-string/
如果不重新启动应用程序本身，则不会更新对使用此渲染器的视图所做的更改。进一步深入研究，视图会被缓存。源代码中的评论提到使用
_razorViewEngine.GetView我得到的是，试图找到一种注册新 ViewRender 的方法，并对 ViewRenderService 进行轻微修改。
//Seems not to be available on asp.net core 2.0...
services.AddMvc().Configure<MvcViewOptions>(options =>
{
options.ViewEngines.Clear();
options.ViewEngines.Add(typeof(CustomViewEngine));
});
并重载 RazorViewEngine 以公开 ViewLookupCache，即视图缓存所在的位置。
public class CustomViewEngine : RazorViewEngine
{
public CustomViewEngine(
IRazorPageFactoryProvider pageFactory,
IRazorPageActivator pageActivator,
HtmlEncoder htmlEncoder,
IOptions<RazorViewEngineOptions> optionsAccessor,
Microsoft.AspNetCore.Razor.Language.RazorProject razorProject,
ILoggerFactory loggerFactory,
System.Diagnostics.DiagnosticSource diagnosticSource) :
base(pageFactory, pageActivator, htmlEncoder, optionsAccessor,razorProject,loggerFactory, diagnosticSource){ }
public void RemoveCachedView(string view)
{
this.ViewLookupCache.Remove(view);
}
}
关于如何在 ASP.NET Core 2.0 中对视图进行缓存以及清除特定视图/一组视图，没有太多可以找到的内容。基本上，出于性能原因，我想找到一种方法，如何将缓存视图的整个选择作为命令刷新。
编辑2018年4月13日
按照 K Finley 的建议，我尝试按照建议清空 ViewLookupCache。代码简述；
在我的startup.cs中的ConfigureServices（不完全确定这是否是自定义视图引擎的注册方式）。
services.AddSingleton<IRazorViewEngine, CustomViewEngine>();
services.AddSingleton<IViewRenderService, ViewRenderService>();
自定义视图引擎：
public class CustomViewEngine : RazorViewEngine
{
public CustomViewEngine(
IRazorPageFactoryProvider pageFactory,
IRazorPageActivator pageActivator,
HtmlEncoder htmlEncoder,
IOptions<RazorViewEngineOptions> optionsAccessor,
Microsoft.AspNetCore.Razor.Language.RazorProject razorProject,
ILoggerFactory loggerFactory,
System.Diagnostics.DiagnosticSource diagnosticSource) :
base(pageFactory, pageActivator, htmlEncoder, optionsAccessor, razorProject, loggerFactory, diagnosticSource)
{ }
public void RemoveViewFromCache(string viewName, string controller, bool isLayout, bool isPartial = false, string pageName = null, string areaName = null)
{
var key = new ViewLocationCacheKey(viewName, controller, areaName, pageName, !isLayout | !isPartial, isLayout ? null : new Dictionary<string, string>(StringComparer.Ordinal));
base.ViewLookupCache.Remove(key);
}
public void RemoveViewFromCache(string viewName, bool isLayout)
{
//Code uses this one
var key = new ViewLocationCacheKey(viewName, isLayout);
base.ViewLookupCache.Remove(key);
}
}
并且修改了原来的ViewRenderService...
public class ViewRenderService : IViewRenderService
{
private CustomViewEngine _razorViewEngine;
private ITempDataProvider _tempDataProvider;
private IServiceProvider _serviceProvider;
private IHostingEnvironment _hostingEnvironment;
public ViewRenderService(IRazorViewEngine razorViewEngine,
ITempDataProvider tempDataProvider,
IServiceProvider serviceProvider,
IHostingEnvironment hostingEnvironment)
{
_razorViewEngine = (CustomViewEngine)razorViewEngine;
...
try
{
using (var sw = new StringWriter())
{
_razorViewEngine.RemoveViewFromCache(viewName, false);
var viewResult = _razorViewEngine.GetView(viewName, viewName, false);
这些修改确实使用第二种方法删除了 ViewLookupCache。然而它仍然没有正确更新我的观点。我确实必须注意这些视图没有自己的控制器。
您需要启用文件监视程序：
在 Dockerfile 中添加环境变量
DOTNET_USE_POLLING_FILE_WATCHER=trueENV DOTNET_USE_POLLING_FILE_WATCHER=true在 ASP.NET Core 2.2 及更高版本中，您可以这样做，
services.Configure<RazorViewEngineOptions>(opts => opts.AllowRecompilingViewsOnFileChange = true);
在ConfigureServices中强制视图引擎在视图发生变化时重新编译视图。
我强烈不同意 Stack Exchanges 违反本文创建许可协议并将我的用户贡献内容出售给 OpenAI 的决定。因此，我正在更新我的所有帖子以包含此消息，并且我已安排删除我的帐户。
凯尔·芬利