如何在ASP.NET Core中使用@ Html.Action代替ViewComponent [英] How to use @Html.Action instead of ViewComponent in ASP.NET Core
问题描述
有什么方法可以在ASP.NET Core中实现@ Html.Action方法(就像在ASP.NET MVC中一样)?我知道ASP.NET Core的ViewComponent功能.但是在某些情况下,我们必须使用Action方法.
Is there any way to implement @Html.Action method in ASP.NET Core (like it was in ASP.NET MVC)? I know about the ViewComponent feature of ASP.NET Core. But there is a scenario when we have to use Action method.
推荐答案
这是将其实现为HtmlHelper扩展的方法.您可以按如下方式使用它:
This is the way to implement this as a HtmlHelper extension. You can use it as follows:
最后一个参数是匿名类型.
The last parameter is an anonymous type.
@ Html.Action("Action");
@Html.Action("Action");
@ Html.Action("Action",新的{字符串a ="a",int i = 5}
@Html.Action("Action", new { string a = "a", int i = 5 }
@ Html.Action("Action","Controller");
@Html.Action("Action", "Controller");
@ Html.Action("Action","Controller",new(字符串a ="a",int i = 5}
@Html.Action("Action", "Controller", new (string a = "a", int i = 5 }
using System;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Html;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Infrastructure;
using Microsoft.AspNetCore.Routing;
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(nameof(controller));
if (controller == null)
throw new ArgumentNullException(nameof(action));
var task = ActionAsync(helper, action, controller, area, parameters);
return task.Result;
}
private static async Task<IHtmlContent> ActionAsync(this IHtmlHelper helper, string action, string controller, string area, object parameters = null)
{
// fetching required services for invocation
var currentHttpContext = helper.ViewContext.HttpContext;
var httpContextFactory = GetServiceOrFail<IHttpContextFactory>(currentHttpContext);
var actionInvokerFactory = GetServiceOrFail<IActionInvokerFactory>(currentHttpContext);
var actionSelector = GetServiceOrFail<IActionDescriptorCollectionProvider>(currentHttpContext);
// creating new action invocation context
var routeData = new RouteData();
var routeParams = new RouteValueDictionary(parameters ?? new { });
var routeValues = new RouteValueDictionary(new { area, controller, action });
var newHttpContext = httpContextFactory.Create(currentHttpContext.Features);
newHttpContext.Response.Body = new MemoryStream();
foreach (var router in helper.ViewContext.RouteData.Routers)
routeData.PushState(router, null, null);
routeData.PushState(null, routeValues, null);
routeData.PushState(null, routeParams, null);
var actionDescriptor = actionSelector.ActionDescriptors.Items.First(i => i.RouteValues["Controller"] == controller && i.RouteValues["Action"] == action);
var actionContext = new ActionContext(newHttpContext, routeData, actionDescriptor);
// invoke action and retreive the response body
var invoker = actionInvokerFactory.CreateInvoker(actionContext);
string content = null;
await invoker.InvokeAsync().ContinueWith(task =>
{
if (task.IsFaulted)
{
content = task.Exception.Message;
}
else if (task.IsCompleted)
{
newHttpContext.Response.Body.Position = 0;
using (var reader = new StreamReader(newHttpContext.Response.Body))
content = reader.ReadToEnd();
}
});
return new HtmlString(content);
}
private static TService GetServiceOrFail<TService>(HttpContext httpContext)
{
if (httpContext == null)
throw new ArgumentNullException(nameof(httpContext));
var service = httpContext.RequestServices.GetService(typeof(TService));
if (service == null)
throw new InvalidOperationException($"Could not locate service: {nameof(TService)}");
return (TService)service;
}
}
}
这篇关于如何在ASP.NET Core中使用@ Html.Action代替ViewComponent的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!