ルーティング

■.NetFramework
App_Start\RouteConfig.cs

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

■.Net Core
Startup.cs

app.UseMvc(routes =>
{
    routes.MapRoute(
        name: "default",
        template: "{controller=Home}/{action=Index}/{id?}");
});