Creating a route constraint

In this recipe, we will learn how to create a route constraint using convention routing.

Getting ready

A route constraint is inserted with an inline syntax, called inline constraints, in the following form: {parameter:constraint}.

There are several ways to create a route constraint:

• Inserting a constraint when creating a route conventionally
• Inserting a constraint when creating an attribute routing
• Creating a class that implements IRouteConstraint

How to do it...

1. Here is the first way, inserting a constraint when creating a route conventionally:

app.UseMvc(routes => 
            { 
                routes.MapRoute( 
                    name: "default", 
                    template: "{controller=Home}/{action=Index}/{id?}" 
                ); 
 
                routes.MapRoute( 
                    name: "products", 
                    template: "Products/{id=1}", 
                    defaults: new { controller = "Product", action = "Details" } 
                ); ...