asp.net-mvc-2 – 如何覆盖ActionLink行为

public static MvcHtmlString AuthorizeActionLink(this HtmlHelper helper,string linkText,string actionName,string controllerName,object routeValues,object htmlAttributes)
{
    if (HasActionPermission(helper,actionName,controllerName))
        return helper.ActionLink(linkText,controllerName,routeValues,htmlAttributes);

    return MvcHtmlString.Empty;
}

public static MvcHtmlString AuthorizeActionLink(this HtmlHelper helper,RouteValueDictionary routeValues,IDictionary<string,object> htmlAttributes)
{
    if (HasActionPermission(helper,htmlAttributes);

    return MvcHtmlString.Empty;
}

在弄清楚用户是否被授权时执行脏工作的方法

static bool HasActionPermission(this HtmlHelper htmlHelper,string controllerName)
{
    ControllerBase controllerToLinkTo = string.IsNullOrEmpty(controllerName)
        ? htmlHelper.ViewContext.Controller
        : GetControllerByName(htmlHelper,controllerName);

    ControllerContext controllerContext = new ControllerContext(htmlHelper.ViewContext.RequestContext,controllerToLinkTo);
    ReflectedControllerDescriptor controllerDescriptor = new ReflectedControllerDescriptor(controllerToLinkTo.GetType());
    ActionDescriptor actionDescriptor = controllerDescriptor.FindAction(controllerContext,actionName);

    return ActionIsAuthorized(controllerContext,actionDescriptor);
}

static bool ActionIsAuthorized(ControllerContext controllerContext,ActionDescriptor actionDescriptor)
{
    if (actionDescriptor == null)
        return false;

    AuthorizationContext authContext = new AuthorizationContext(controllerContext,actionDescriptor);
    foreach (IAuthorizationFilter authFilter in actionDescriptor.GetFilters().AuthorizationFilters)
    {
        authFilter.OnAuthorization(authContext);

        if (authContext.Result != null)
            return false;
    }

    return true;
}

static ControllerBase GetControllerByName(HtmlHelper helper,string controllerName)
{
    IControllerFactory factory = ControllerBuilder.Current.GetControllerFactory();

    IController controller = factory.CreateController(helper.ViewContext.RequestContext,controllerName);

    if (controller == null)
    {
        throw new InvalidOperationException(
            string.Format(
                CultureInfo.CurrentUICulture,"Controller factory {0} controller {1} returned null",factory.GetType(),controllerName));
    }

    return (ControllerBase)controller;
}