31

Here is my scenario. For the example lets say that I need to return a list of cars based on a search criteria. I would like to have a single View to display the results since the output will be the same, but I need several ways of getting there. For instance, I may have a Form with a textbox to search by year. I may have another separate page that contains a hyperlink for all red, Toyota cars. How do I handle these multiple scenarios in the same View and Controller. My dilemma is that the search could contain several options… year, make, model, etc but I don’t know where to put them.

What is the best approach for this? Should I define the parameters in the routing or go with query strings, etc?

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3 Answers 3

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77

Option 1

Of course you always can choose the way of /car/search/?vendor=Toyota&color=Red&model=Corola and I think it will be good for you.

routes.MapRoute(
    "CarSearch",
    "car/search",
    new { controller = "car", action = "search" }
);

You can get params from Request.Params in action in this case.

Option 2

Or you can define params in the routing table, but AFAIK it will be required to make a set of rules for all possible combinations, because an order of the params matter, for example:

        routes.MapRoute(
            "CarSearch1",
            "car/search/vendor/{vendor}/color/{color}/model/{model}",
            new {controller = "car", action = "search"}
        );

        routes.MapRoute(
            "CarSearch2",
            "car/search/color/{color}/vendor/{vendor}/model/{model}",
            new {controller = "car", action = "search"}
        );

        routes.MapRoute(
            "CarSearch3",
            "car/search/model/{model}/color/{color}/vendor/{vendor}",
            new {controller = "car", action = "search"}
        );

... an so on. It's true if you are going with the standard MvcRouteHandler.

But it was an easy ways :)

Option 3

The hard, but, I think, most elegant way, is to make your own IRouteHandler implementation - it will give you much more flexibility in params order. But again, its a hard way, dont go with it if you have a simple app. So, just for example of how to make it this way (very simple example):

Add new route to the list of routes:

routes.Add
    (
        new Route
            (
                "car/search/{*data}",
                new RouteValueDictionary(new {controller = "car", action = "search", data = ""}),
                new MyRouteHandler()
            )
    );

Add classes that will tweak the standard request processing chain:

class MyRouteHandler : IRouteHandler
{
    public IHttpHandler GetHttpHandler(RequestContext requestContext)
    {
        return new MyHttpHandler(requestContext);
    }
}

class MyHttpHandler : MvcHandler
{
    public MyHttpHandler(RequestContext requestContext) : base(requestContext)
    {
    }

    protected override void ProcessRequest(HttpContextBase httpContext)
    {
        IController controller = new CarController();
        (controller as Controller).ActionInvoker = new MyActionInvoker();
        controller.Execute(RequestContext);
    }
}

class MyActionInvoker : ControllerActionInvoker
{
    protected override ActionResult InvokeActionMethod(MethodInfo methodInfo, IDictionary<string, object> parameters)
    {
        // if form of model/{model}/color/{color}/vendor/{vendor}
        var data = ControllerContext.RouteData.GetRequiredString("data");
        var tokens = data.Split('/');

        var searchParams = new Dictionary<string, string>();
        for (var i = 0; i < tokens.Length; i++)
        {
            searchParams.Add(tokens[i], tokens[++i]);
        }

        parameters["searchParams"] = searchParams;

        return base.InvokeActionMethod(methodInfo, parameters);
    }
}

In controller:

public ActionResult Search(IDictionary<string, string> searchParams)
{
    ViewData.Add
        (
            // output 'model = Corola, color = red, vendor = Toyota'
            "SearchParams",
            string.Join(", ", searchParams.Select(pair => pair.Key + " = " + pair.Value).ToArray())
        );
    return View();
}

And it will work with any search parameters order:

/car/search/vendor/Toyota/color/red/model/Corola
/car/search/color/red/model/Corola/vendor/Toyota
/car/search/model/Corola/color/red/vendor/Toyota

But also dont forget to make a link generation logic, because Html.ActionLink and Html.RenderLink will not give you url in pretty form of /car/search/model/Corola/color/red/vendor/Toyota, so you'll need to make a custom link generator.

So, if you need a really flexible routing - you'd better go with this hard way :)

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4 Comments

I think that my best course of action at the moment will be Option 1. Option 2 was the way I was initially headed, but it seems inefficient to have to put all possible routing combinations. Option 3 looks good for later if I want to refactor, but being an MVC NOOB I'll stick with the easy route.
I dont think i have enough pts to vote up yet, but I'll get there ;)
@maxnk Are there any dummy projects of this you know of?
@CR41G14 I do not aware of such projects, but you can use this code as a kickstart to make your own custom solution. Just note that it was written in time of MVC 1.0, so some small tweaks may need to be done.
0

Each method (action) on the controller would take different parameters, but create the same collection of search results. Then, each would 

return View("SearchResult", searchResultCollection);

They all use the same view, SearchResult.aspx.

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Comments

0

Something along these lines should do what you're after. Notice how there's two different action methods, but both of them return a call to DisplayResults() - so they end up using the same view, with different ViewData.

public class SearchController : Controller {

    public ActionResult ByColor(Color[] colors) {
         List<Car> results = carRepository.FindByColor(colors);
         return(DisplayResults(result));
    }

    public ActionResult ByMake(string make) {
         List<Car> results = carRepository.FindByMake(make);
         return(DisplayResults(results));
    }

    private ActionResult DisplayResults(IList<Car> results) {

        // Here we explicitly return the view /Views/Search/Results.aspx
        // by specifying the view name in the call to View();
        return(View("Results", results));
    }
}
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1 Comment

Thanks. Your example is how my thinking started, but I think my lack of understanding for MVC routing caused me to get stumped. I've only been looking at it for a few days. How would you pass an Array of colors to the ActionResult. My understanding is that these params come from URL

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