Razor Pages route and app conventions in ASP.NET Core

Learn how to use page route and app model provider conventions to control page routing, discovery, and processing in Razor Pages apps.

To specify a page route, add route segments, or add parameters to a route, use the page's @page directive. For more information, see Custom routes.

There are reserved words that can't be used as route segments or parameter names. For more information, see Routing: Reserved routing names.

View or download sample code (how to download)

Scenario	The sample demonstrates
Model conventions Conventions.Add IPageRouteModelConvention IPageApplicationModelConvention IPageHandlerModelConvention	Add a route template and header to an app's pages.
Page route action conventions AddFolderRouteModelConvention AddPageRouteModelConvention AddPageRoute	Add a route template to pages in a folder and to a single page.
Page model action conventions AddFolderApplicationModelConvention AddPageApplicationModelConvention ConfigureFilter (filter class, lambda expression, or filter factory)	Add a header to pages in a folder, add a header to a single page, and configure a filter factory to add a header to an app's pages.

Razor Pages conventions are configured using an AddRazorPages overload that configures RazorPagesOptions. The following convention examples are explained later in this topic:

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddRazorPages(options =>
    {
        options.Conventions.Add( ... );
        options.Conventions.AddFolderRouteModelConvention(
            "/OtherPages", model => { ... });
        options.Conventions.AddPageRouteModelConvention(
            "/About", model => { ... });
        options.Conventions.AddPageRoute(
            "/Contact", "TheContactPage/{text?}");
        options.Conventions.AddFolderApplicationModelConvention(
            "/OtherPages", model => { ... });
        options.Conventions.AddPageApplicationModelConvention(
            "/About", model => { ... });
        options.Conventions.ConfigureFilter(model => { ... });
        options.Conventions.ConfigureFilter( ... );
    });
}

Route order

Routes specify an Order for processing (route matching).

Route order	Behavior
-1	The route is processed before other routes are processed.
0	Order isn't specified (default value). Not assigning Order (Order = null) defaults the route Order to 0 (zero) for processing.
1, 2, … n	Specifies the route processing order.

Route processing is established by convention:

• Routes are processed in sequential order (-1, 0, 1, 2, … n).
• When routes have the same Order, the most specific route is matched first followed by less specific routes.
• When routes with the same Order and the same number of parameters match a request URL, routes are processed in the order that they're added to the PageConventionCollection.

If possible, avoid depending on an established route processing order. Generally, routing selects the correct route with URL matching. If you must set route Order properties to route requests correctly, the app's routing scheme is probably confusing to clients and fragile to maintain. Seek to simplify the app's routing scheme. The sample app requires an explicit route processing order to demonstrate several routing scenarios using a single app. However, you should attempt to avoid the practice of setting route Order in production apps.

Razor Pages routing and MVC controller routing share an implementation. Information on route order in the MVC topics is available at Routing to controller actions: Ordering attribute routes.

Model conventions

Add a delegate for IPageConvention to add model conventions that apply to Razor Pages.

Add a route model convention to all pages

Use Conventions to create and add an IPageRouteModelConvention to the collection of IPageConvention instances that are applied during page route model construction.

The sample app contains the GlobalTemplatePageRouteModelConvention class to add a {globalTemplate?} route template to all of the pages in the app:

using Microsoft.AspNetCore.Mvc.ApplicationModels;
namespace SampleApp.Conventions;

public class GlobalTemplatePageRouteModelConvention : IPageRouteModelConvention
{
    public void Apply(PageRouteModel model)
    {
        var selectorCount = model.Selectors.Count;
        for (var i = 0; i < selectorCount; i++)
        {
            var selector = model.Selectors[i];
            model.Selectors.Add(new SelectorModel
            {
                AttributeRouteModel = new AttributeRouteModel
                {
                    Order = 1,
                    Template = AttributeRouteModel.CombineTemplates(
                        selector.AttributeRouteModel!.Template, 
                        "{globalTemplate?}"),
                }
            });
        }
    }
}

In the preceding code:

• The PageRouteModel is passed to the Apply method.
• The PageRouteModel.Selectors gets the count of selectors.
• A new SelectorModel is added which contains a AttributeRouteModel

Razor Pages options, such as adding Conventions, are added when Razor Pages is added to the service collection. For an example, see the sample app.

using Microsoft.AspNetCore.Mvc.ApplicationModels;
using Microsoft.EntityFrameworkCore;
using SampleApp.Conventions;
using SampleApp.Data;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddDbContext<AppDbContext>(options =>
                                   options.UseInMemoryDatabase("InMemoryDb"));

builder.Services.AddRazorPages(options =>
   {
       options.Conventions.Add(new GlobalTemplatePageRouteModelConvention());

       options.Conventions.AddFolderRouteModelConvention("/OtherPages", model =>
       {
           var selectorCount = model.Selectors.Count;
           for (var i = 0; i < selectorCount; i++)
           {
               var selector = model.Selectors[i];
               model.Selectors.Add(new SelectorModel
               {
                   AttributeRouteModel = new AttributeRouteModel
                   {
                       Order = 2,
                       Template = AttributeRouteModel.CombineTemplates(
                           selector.AttributeRouteModel!.Template,
                           "{otherPagesTemplate?}"),
                   }
               });
           }
       });

       options.Conventions.AddPageRouteModelConvention("/About", model =>
       {
           var selectorCount = model.Selectors.Count;
           for (var i = 0; i < selectorCount; i++)
           {
               var selector = model.Selectors[i];
               model.Selectors.Add(new SelectorModel
               {
                   AttributeRouteModel = new AttributeRouteModel
                   {
                       Order = 2,
                       Template = AttributeRouteModel.CombineTemplates(
                           selector.AttributeRouteModel!.Template,
                           "{aboutTemplate?}"),
                   }
               });
           }
       });

   });

var app = builder.Build();

if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Error");
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseAuthorization();
app.MapRazorPages();
app.Run();

Consider the GlobalTemplatePageRouteModelConvention class:

using Microsoft.AspNetCore.Mvc.ApplicationModels;
namespace SampleApp.Conventions;

public class GlobalTemplatePageRouteModelConvention : IPageRouteModelConvention
{
    public void Apply(PageRouteModel model)
    {
        var selectorCount = model.Selectors.Count;
        for (var i = 0; i < selectorCount; i++)
        {
            var selector = model.Selectors[i];
            model.Selectors.Add(new SelectorModel
            {
                AttributeRouteModel = new AttributeRouteModel
                {
                    Order = 1,
                    Template = AttributeRouteModel.CombineTemplates(
                        selector.AttributeRouteModel!.Template, 
                        "{globalTemplate?}"),
                }
            });
        }
    }
}

The Order property for the AttributeRouteModel is set to 1. This ensures the following route matching behavior in the sample app:

• A route template for TheContactPage/{text?} is added later in this topic. The Contact Page route has a default order of null (Order = 0), so it matches before the {globalTemplate?} route template which has Order = 1.

• The {aboutTemplate?} route template is show in the preceding code. The {aboutTemplate?} template is given an Order of 2. When the About page is requested at /About/RouteDataValue, "RouteDataValue" is loaded into RouteData.Values["globalTemplate"] (Order = 1) and not RouteData.Values["aboutTemplate"] (Order = 2) due to setting the Order property.

• The {otherPagesTemplate?} route template is shown in the preceding code. The {otherPagesTemplate?} template is given an Order of 2. When any page in the Pages/OtherPages folder is requested with a route parameter:

• For example, /OtherPages/Page1/xyz

• The route data value "xyz" is loaded into RouteData.Values["globalTemplate"] (Order = 1).

• RouteData.Values["otherPagesTemplate"] with (Order = 2) is not loaded due to the Order property 2 having a higher value.

When possible, don't set the Order. When Order is not set, it defaults to Order = 0. Rely on routing to select the correct route rather than the Order property.

Request the sample's About page at localhost:{port}/About/GlobalRouteValue and inspect the result:

The sample app uses the Rick.Docs.Samples.RouteInfo NuGet package to display routing information in the logging output. Using localhost:{port}/About/GlobalRouteValue, the logger displays the request, the Order, and the template used:

info: SampleApp.Pages.AboutModel[0]
       /About/GlobalRouteValue   Order = 1 Template = About/{globalTemplate?}

Add an app model convention to all pages

Use Conventions to create and add an IPageApplicationModelConvention to the collection of IPageConvention instances that are applied during page app model construction.

To demonstrate this and other conventions later in the topic, the sample app includes an AddHeaderAttribute class. The class constructor accepts a name string and a values string array. These values are used in its OnResultExecuting method to set a response header. The full class is shown in the Page model action conventions section later in the topic.

The sample app uses the AddHeaderAttribute class to add a header, GlobalHeader, to all of the pages in the app:

public class GlobalHeaderPageApplicationModelConvention 
    : IPageApplicationModelConvention
{
    public void Apply(PageApplicationModel model)
    {
        model.Filters.Add(new AddHeaderAttribute(
            "GlobalHeader", new string[] { "Global Header Value" }));
    }
}

Program.cs:

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseInMemoryDatabase("InMemoryDb"));

builder.Services.AddRazorPages(options =>
   {
       options.Conventions.Add(new GlobalTemplatePageRouteModelConvention());

       options.Conventions.Add(new GlobalHeaderPageApplicationModelConvention());

Request the sample's About page at localhost:{port}/About and inspect the headers to view the result:

Add a handler model convention to all pages

Use Conventions to create and add an IPageHandlerModelConvention to the collection of IPageConvention instances that are applied during page handler model construction.

public class GlobalPageHandlerModelConvention
    : IPageHandlerModelConvention
{
    public void Apply(PageHandlerModel model)
    {
        // Access the PageHandlerModel
    }
}

Page route action conventions

The default route model provider that derives from IPageRouteModelProvider invokes conventions which are designed to provide extensibility points for configuring page routes.

Folder route model convention

Use AddFolderRouteModelConvention to create and add an IPageRouteModelConvention that invokes an action on the PageRouteModel for all of the pages under the specified folder.

The sample app uses AddFolderRouteModelConvention to add an {otherPagesTemplate?} route template to the pages in the OtherPages folder:

options.Conventions.AddFolderRouteModelConvention("/OtherPages", model =>
{
    var selectorCount = model.Selectors.Count;
    for (var i = 0; i < selectorCount; i++)
    {
        var selector = model.Selectors[i];
        model.Selectors.Add(new SelectorModel
        {
            AttributeRouteModel = new AttributeRouteModel
            {
                Order = 2,
                Template = AttributeRouteModel.CombineTemplates(
                    selector.AttributeRouteModel!.Template,
                    "{otherPagesTemplate?}"),
            }
        });
    }
});

The Order property for the AttributeRouteModel is set to 2. This ensures that the template for {globalTemplate?} (set earlier in the topic to 1) is given priority for the first route data value position when a single route value is provided. If a page in the Pages/OtherPages folder is requested with a route parameter value (for example, /OtherPages/Page1/RouteDataValue), "RouteDataValue" is loaded into RouteData.Values["globalTemplate"] (Order = 1) and not RouteData.Values["otherPagesTemplate"] (Order = 2) due to setting the Order property.

Wherever possible, don't set the Order, which results in Order = 0. Rely on routing to select the correct route.

Request the sample's Page1 page at localhost:5000/OtherPages/Page1/GlobalRouteValue/OtherPagesRouteValue and inspect the result:

Page route model convention

Use AddPageRouteModelConvention to create and add an IPageRouteModelConvention that invokes an action on the PageRouteModel for the page with the specified name.

The sample app uses AddPageRouteModelConvention to add an {aboutTemplate?} route template to the About page:

options.Conventions.AddPageRouteModelConvention("/About", model =>
{
    var selectorCount = model.Selectors.Count;
    for (var i = 0; i < selectorCount; i++)
    {
        var selector = model.Selectors[i];
        model.Selectors.Add(new SelectorModel
        {
            AttributeRouteModel = new AttributeRouteModel
            {
                Order = 2,
                Template = AttributeRouteModel.CombineTemplates(
                    selector.AttributeRouteModel!.Template,
                    "{aboutTemplate?}"),
            }
        });
    }
});

The Order property for the AttributeRouteModel is set to 2. This ensures that the template for {globalTemplate?} (set earlier in the topic to 1) is given priority for the first route data value position when a single route value is provided. If the About page is requested with a route parameter value at /About/RouteDataValue, "RouteDataValue" is loaded into RouteData.Values["globalTemplate"] (Order = 1) and not RouteData.Values["aboutTemplate"] (Order = 2) due to setting the Order property.

Wherever possible, don't set the Order, which results in Order = 0. Rely on routing to select the correct route.

Request the sample's About page at localhost:{port}/About/GlobalRouteValue/AboutRouteValue and inspect the result:

The logger output displays:

info: SampleApp.Pages.AboutModel[0]
       /About/GlobalRouteValue/AboutRouteValue   Order = 2 Template = About/{globalTemplate?}/{aboutTemplate?}

Use a parameter transformer to customize page routes

See Parameter transformers.

Configure a page route

Use AddPageRoute to configure a route to a page at the specified page path. Generated links to the page use the specified route. AddPageRoute uses AddPageRouteModelConvention to establish the route.

The sample app creates a route to /TheContactPage for the Contact Razor Page:

options.Conventions.AddPageRoute("/Contact", "TheContactPage/{text?}");

The Contact page can also be reached at /Contact1` via its default route.

The sample app's custom route to the Contact page allows for an optional text route segment ({text?}). The page also includes this optional segment in its @page directive in case the visitor accesses the page at its /Contact route:

@page "{text?}"
@model ContactModel
@{
    ViewData["Title"] = "Contact";
}

<h1>@ViewData["Title"]</h1>
<h2>@Model.Message</h2>

<address>
    One Microsoft Way<br>
    Redmond, WA 98052-6399<br>
    <abbr title="Phone">P:</abbr>
    425.555.0100
</address>

<address>
    <strong>Support:</strong> <a href="mailto:Support@example.com">Support@example.com</a><br>
    <strong>Marketing:</strong> <a href="mailto:Marketing@example.com">Marketing@example.com</a>
</address>

<p>@Model.RouteDataTextTemplateValue</p>

Note that the URL generated for the Contact link in the rendered page reflects the updated route:

Visit the Contact page at either its ordinary route, /Contact, or the custom route, /TheContactPage. If you supply an additional text route segment, the page shows the HTML-encoded segment that you provide:

Page model action conventions

The default page model provider that implements IPageApplicationModelProvider invokes conventions which are designed to provide extensibility points for configuring page models. These conventions are useful when building and modifying page discovery and processing scenarios.

For the examples in this section, the sample app uses an AddHeaderAttribute class, which is a ResultFilterAttribute, that applies a response header:

public class AddHeaderAttribute : ResultFilterAttribute
{
    private readonly string _name;
    private readonly string[] _values;

    public AddHeaderAttribute(string name, string[] values)
    {
        _name = name;
        _values = values;
    }

    public override void OnResultExecuting(ResultExecutingContext context)
    {
        context.HttpContext.Response.Headers.Add(_name, _values);
        base.OnResultExecuting(context);
    }
}

Using conventions, the sample demonstrates how to apply the attribute to all of the pages in a folder and to a single page.

Folder app model convention

Use AddFolderApplicationModelConvention to create and add an IPageApplicationModelConvention that invokes an action on PageApplicationModel instances for all pages under the specified folder.

The sample demonstrates the use of AddFolderApplicationModelConvention by adding a header, OtherPagesHeader, to the pages inside the OtherPages folder of the app:

options.Conventions.AddFolderApplicationModelConvention("/OtherPages", model =>
{
    model.Filters.Add(new AddHeaderAttribute(
        "OtherPagesHeader", new string[] { "OtherPages Header Value" }));
});

Request the sample's Page1 page at localhost:5000/OtherPages/Page1 and inspect the headers to view the result:

Page app model convention

Use AddPageApplicationModelConvention to create and add an IPageApplicationModelConvention that invokes an action on the PageApplicationModel for the page with the specified name.

The sample demonstrates the use of AddPageApplicationModelConvention by adding a header, AboutHeader, to the About page:

options.Conventions.AddPageApplicationModelConvention("/About", model =>
{
    model.Filters.Add(new AddHeaderAttribute(
        "AboutHeader", new string[] { "About Header Value" }));
});

Request the sample's About page at localhost:5000/About and inspect the headers to view the result:

Configure a filter

ConfigureFilter configures the specified filter to apply. You can implement a filter class, but the sample app shows how to implement a filter in a lambda expression, which is implemented behind-the-scenes as a factory that returns a filter:

options.Conventions.ConfigureFilter(model =>
{
    if (model.RelativePath.Contains("OtherPages/Page2"))
    {
        return new AddHeaderAttribute(
            "OtherPagesPage2Header",
            new string[] { "OtherPages/Page2 Header Value" });
    }
    return new EmptyFilter();
});

The page app model is used to check the relative path for segments that lead to the Page2 page in the OtherPages folder. If the condition passes, a header is added. If not, the EmptyFilter is applied.

EmptyFilter is an Action filter. Since Action filters are ignored by Razor Pages, the EmptyFilter has no effect as intended if the path doesn't contain OtherPages/Page2.

Request the sample's Page2 page at localhost:5000/OtherPages/Page2 and inspect the headers to view the result:

Configure a filter factory

ConfigureFilter configures the specified factory to apply filters to all Razor Pages.

The sample app provides an example of using a filter factory by adding a header, FilterFactoryHeader, with two values to the app's pages:

options.Conventions.ConfigureFilter(new AddHeaderWithFactory());

AddHeaderWithFactory.cs:

public class AddHeaderWithFactory : IFilterFactory
{
    // Implement IFilterFactory
    public IFilterMetadata CreateInstance(IServiceProvider serviceProvider)
    {
        return new AddHeaderFilter();
    }

    private class AddHeaderFilter : IResultFilter
    {
        public void OnResultExecuting(ResultExecutingContext context)
        {
            context.HttpContext.Response.Headers.Add(
                "FilterFactoryHeader", 
                new string[] 
                { 
                    "Filter Factory Header Value 1",
                    "Filter Factory Header Value 2"
                });
        }

        public void OnResultExecuted(ResultExecutedContext context)
        {
        }
    }

    public bool IsReusable
    {
        get
        {
            return false;
        }
    }
}

Request the sample's About page at localhost:5000/About and inspect the headers to view the result:

MVC Filters and the Page filter (IPageFilter)

MVC Action filters are ignored by Razor Pages, since Razor Pages use handler methods. Other types of MVC filters are available for you to use: Authorization, Exception, Resource, and Result. For more information, see the Filters topic.

The Page filter (IPageFilter) is a filter that applies to Razor Pages. For more information, see Filter methods for Razor Pages.

Additional resources

• Razor Pages Routing
• Razor Pages authorization conventions in ASP.NET Core
• Areas in ASP.NET Core