[英]How to get the urlHelper from html helper context in asp.net core mvc html helper static method
我在ASP.NET 5 RC1
有一個項目,我用來從 HTMLHelper 靜態方法中的 HtmlHelper 上下文獲取 urlHelper
public static IHtmlContent MyHtmlHelperMethod<TModel, TResult>(
this IHtmlHelper<TModel> htmlHelper,
Expression<Func<TModel, TResult>> expression)
{
//get the context from the htmlhelper and use it to get the urlHelper as it isn't passed to the method from the view
var urlHelper = GetContext(htmlHelper).RequestServices.GetRequiredService<IUrlHelper>();
var controller = htmlHelper.ViewContext.RouteData.Values["controller"].ToString();
string myLink;
if (htmlHelper.ViewContext.RouteData.Values["area"] == null)
{
myLink= urlHelper.Action("index", controller);
} else
{
string area = htmlHelper.ViewContext.RouteData.Values["area"].ToString();
myLink = urlHelper.Action("index", controller, new { area = area });
}
string output = "<div><a href = \"" + myLink + "\" class=\"myclass\"><blabla></blabla>My Link</a></div>;
return new HtmlString(output.ToString());
}
但是在ASP.NET Core
它不再起作用並且我收到運行時錯誤
>InvalidOperationException: No service for type 'Microsoft.AspNetCore.Mvc.IUrlHelper' has been registered.
張貼在解決這個計算器的答案是注入IUrlHelperFactory
,但是我使用靜態的HTML幫助我在調用方法cshtml
,而不是它在taghelpers使用的類。
如何更改我的代碼以在ASP.net Core
工作?
將您的原始代碼更改為:
var urlHelperFactory = GetContext(htmlHelper).RequestServices.GetRequiredService<IUrlHelperFactory>();
var actionContext = GetContext(htmlHelper).RequestServices.GetRequiredService<IActionContextAccessor>().ActionContext;
var urlHelper = urlHelperFactory.GetUrlHelper(actionContext);
微軟可能在 .net core 2.1 中做了一些改動。 它比接受的答案稍微簡單。 我希望這對某人有幫助。
using Microsoft.AspNetCore.Html;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.Routing;
using Microsoft.Extensions.DependencyInjection;
namespace MyApp.Extensions
{
public static class WebApiHelperExtension
{
public static IHtmlContent WebApiUrl(this IHtmlHelper htmlHelper)
{
var urlHelperFactory = htmlHelper.ViewContext.HttpContext.RequestServices.GetRequiredService<IUrlHelperFactory>();
var urlHelper = urlHelperFactory.GetUrlHelper(htmlHelper.ViewContext);
//...
}
}
}
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