@Html.ActionAsp.net Core 在哪里?我可以看到@Html.ActionLink但不能像以前一样直接调用Action。
@Html.Action
@Html.ActionLink
它被ViewComponents取代了吗?
更新:从2.2.2版本开始,HttpContextAccessor将上下文保留在一个对象中(据说是为了防止请求之间的混淆),这会影响当前解决方案…因此,您需要为IHttpContextAccessor(旧版本)提供以下实现并进行注册作为一个单例:
public class HttpContextAccessor : IHttpContextAccessor { private static AsyncLocal<HttpContext> _httpContextCurrent = new AsyncLocal<HttpContext>(); HttpContext IHttpContextAccessor.HttpContext { get => _httpContextCurrent.Value; set => _httpContextCurrent.Value = value; } }
对于asp.net core 2
using Microsoft.AspNetCore.Html; using Microsoft.AspNetCore.Http; using Microsoft.AspNetCore.Mvc.Infrastructure; using Microsoft.AspNetCore.Routing; using Microsoft.Extensions.DependencyInjection; using System; using System.IO; using System.Threading.Tasks; namespace Microsoft.AspNetCore.Mvc.Rendering { public static class HtmlHelperViewExtensions { public static IHtmlContent Action(this IHtmlHelper helper, string action, object parameters = null) { var controller = (string)helper.ViewContext.RouteData.Values["controller"]; return Action(helper, action, controller, parameters); } public static IHtmlContent Action(this IHtmlHelper helper, string action, string controller, object parameters = null) { var area = (string)helper.ViewContext.RouteData.Values["area"]; return Action(helper, action, controller, area, parameters); } public static IHtmlContent Action(this IHtmlHelper helper, string action, string controller, string area, object parameters = null) { if (action == null) throw new ArgumentNullException("action"); if (controller == null) throw new ArgumentNullException("controller"); var task = RenderActionAsync(helper, action, controller, area, parameters); return task.Result; } private static async Task<IHtmlContent> RenderActionAsync(this IHtmlHelper helper, string action, string controller, string area, object parameters = null) { // fetching required services for invocation var serviceProvider = helper.ViewContext.HttpContext.RequestServices; var actionContextAccessor = helper.ViewContext.HttpContext.RequestServices.GetRequiredService<IActionContextAccessor>(); var httpContextAccessor = helper.ViewContext.HttpContext.RequestServices.GetRequiredService<IHttpContextAccessor>(); var actionSelector = serviceProvider.GetRequiredService<IActionSelector>(); // creating new action invocation context var routeData = new RouteData(); foreach (var router in helper.ViewContext.RouteData.Routers) { routeData.PushState(router, null, null); } routeData.PushState(null, new RouteValueDictionary(new { controller = controller, action = action, area = area }), null); routeData.PushState(null, new RouteValueDictionary(parameters ?? new { }), null); //get the actiondescriptor RouteContext routeContext = new RouteContext(helper.ViewContext.HttpContext) { RouteData = routeData }; var candidates = actionSelector.SelectCandidates(routeContext); var actionDescriptor = actionSelector.SelectBestCandidate(routeContext, candidates); var originalActionContext = actionContextAccessor.ActionContext; var originalhttpContext = httpContextAccessor.HttpContext; try { var newHttpContext = serviceProvider.GetRequiredService<IHttpContextFactory>().Create(helper.ViewContext.HttpContext.Features); if (newHttpContext.Items.ContainsKey(typeof(IUrlHelper))) { newHttpContext.Items.Remove(typeof(IUrlHelper)); } newHttpContext.Response.Body = new MemoryStream(); var actionContext = new ActionContext(newHttpContext, routeData, actionDescriptor); actionContextAccessor.ActionContext = actionContext; var invoker = serviceProvider.GetRequiredService<IActionInvokerFactory>().CreateInvoker(actionContext); await invoker.InvokeAsync(); newHttpContext.Response.Body.Position = 0; using (var reader = new StreamReader(newHttpContext.Response.Body)) { return new HtmlString(reader.ReadToEnd()); } } catch (Exception ex) { return new HtmlString(ex.Message); } finally { actionContextAccessor.ActionContext = originalActionContext; httpContextAccessor.HttpContext = originalhttpContext; if (helper.ViewContext.HttpContext.Items.ContainsKey(typeof(IUrlHelper))) { helper.ViewContext.HttpContext.Items.Remove(typeof(IUrlHelper)); } } } } }
它基于白羊座的反应。我更正了2.0版未编译的内容,并添加了一些调整。当前的httpcontext和当前的actioncontext有2个美化的静态值。在httpcontext中IHttpContextFactory.Create设置了一个,在代码中设置了actioncontext。请注意,这取决于你使用的功能IActionContextAccessor,并IHttpContextAccessor可能不会被默认注册,所以你可能需要将其添加在启动:
IHttpContextFactory.Create
IActionContextAccessor
IHttpContextAccessor
services.AddSingleton<IActionContextAccessor, ActionContextAccessor>(); services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
services.AddSingleton<IActionContextAccessor, ActionContextAccessor>();
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
HttpContext只是一个包装器HttpContext.Features,因此,如果您在其中一个进行更改,则在另一个中也进行更改…我将在try / catch的最后部分重设我所了解的内容。
HttpContext.Features
我IUrlHelper从Items缓存中删除了,因为即使构建urlHelper的actionContext不同,该值也将被重用IUrlHelperFactory.GetUrlHelper。
IUrlHelper
IUrlHelperFactory.GetUrlHelper
Asp.net Core 2.0假设您不会这样做,那么很有可能还有其他缓存的东西,因此我建议在使用此方法时要格外小心,如果不需要,请不要这样做。