Question

I have a question, can this be done using ASP.NET MVC (Razor, and MapRoute)?

Example

• Category/ – calls controller Category and Index function
• Category/{State_name} – calls controller Category and Cities(State_id) function, returns all cities inside that state.

So URL is displaying state name , but Cities function receive state id?

Answer 1

Yes u can, try

public class CategoryController : Controller {

    // GET: /Category/
    // OR
    // GET: /Category/State_name
    public ActionResult Index(string State_name) {
        if (!string.IsNullOrWhiteSpace(State_name)) {
            int? State_id = FindStateIdFromStateName(State_name); // retrive state_id from datastore where state_name == State_name
            if (State_id.HasValue) { // means the currect state_name passed to action
                var model = FindStateById(State_id.Value);
                return View("Cities", model); // will renders Cities.cshtml with specified model
            } else {
                // means the specified state_name not found! u can do something else, or allow continue bellow lines
            }
        }
        return View(); // will render normal Index.cshtml
    }

}

Let me know if you have any questions or need clarifications on any part.

UPDATE

I have one issue with the way! You get the ID from db with State_name, then get the model from db by State_name! Why not retrieve
model from db by State_name at the first time?
look:

public class CategoryController : Controller {

    // GET: /Category/
    // OR
    // GET: /Category/State_name
    public ActionResult Index(string State_name) {
        if (!string.IsNullOrWhiteSpace(State_name)) {
            var model = FindStateByName(State_name);
            if(model != null)
                return View("Cities", model);
            else
                // means the specified state_name not found! u can do something else, or allow continue bellow lines
        }
        return View(); // will render normal Index.cshtml
    }

}

and if you are on EF, then you can create this method:

public State FindStateByName(state_name){
    using(var context = new YourEntityContext()){
         return context.States.SingleOrDefault(s => s.Name.ToLower() == state_name.ToLower());
    }
}

Why not using this way?