如何构建仅用于操作和带有 id 的控制器的路由？答案

【问题标题】：How to build routes only to action and to controller with id?如何构建仅用于操作和带有 id 的控制器的路由？
【发布时间】：2018-09-27 11:59:27
【问题描述】：

我正在尝试构建两条路线，仅用于操作和带有 id 的控制器，保持默认。

我必须访问：

www.mysite.com/MyController/MyAction/{OptionalId}
www.mysite.com/MyController/{OptionalId}
www.mysite.com/MyActionFromHomeController

我能够创建路线来处理第一点和第三点，但不能用于第二点。当前代码：

public class RouteConfig
{
    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

        routes.MapRoute(
            name: "OnlyActionToHomeController",
            url: "{action}",
            defaults: new { controller = "Home" },
            constraints: new { noConflictingControllerExists = new NoConflictingControllerExists() }
        );

        routes.MapRoute(
            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
        );
    }
}

public class NoConflictingControllerExists : IRouteConstraint
{
    private static readonly Dictionary<string, bool> _cache = new Dictionary<string, bool>(StringComparer.OrdinalIgnoreCase);

    public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
    {
        var path = httpContext.Request.Path;

        if (path == "/" || String.IsNullOrEmpty(path))
            return false;

        if (_cache.ContainsKey(path))
            return _cache[path];

        IController ctrl;

        try
        {
            var ctrlFactory = ControllerBuilder.Current.GetControllerFactory();
            ctrl = ctrlFactory.CreateController(httpContext.Request.RequestContext, values["action"] as string);
        }
        catch
        {
            _cache.Add(path, true);
            return true;
        }

        var res = ctrl == null;
        _cache.Add(path, res);

        return res;
    }
}

【问题讨论】：

标签： asp.net asp.net-mvc routing asp.net-mvc-routing

【解决方案1】：

我做到了！

public class RouteConfig
{
    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

        routes.MapRoute(
            name: "OnlyController",
            url: "{controller}/{id}",
            defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },
            constraints: new { id = @"\d+" } // define the id parameter needs to be integer
        );

        routes.MapRoute(
            name: "OnlyActionToHomeController",
            url: "{action}",
            defaults: new { controller = "Home" },
            constraints: new { noConflictingControllerExists = new NoConflictingControllerExists() }
        );

        routes.MapRoute(
            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
        );
    }
}

public class NoConflictingControllerExists : IRouteConstraint
{
    private static readonly Dictionary<string, bool> _cache = new Dictionary<string, bool>(StringComparer.OrdinalIgnoreCase);

    public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
    {
        var path = httpContext.Request.Path;

        if (path == "/" || String.IsNullOrEmpty(path))
            return false;

        if (_cache.ContainsKey(path))
            return _cache[path];

        IController ctrl;

        try
        {
            var ctrlFactory = ControllerBuilder.Current.GetControllerFactory();
            ctrl = ctrlFactory.CreateController(httpContext.Request.RequestContext, values["action"] as string);
        }
        catch
        {
            _cache.Add(path, true);
            return true;
        }

        var res = ctrl == null;
        _cache.Add(path, res);

        return res;
    }
}

【讨论】：