Maintain the querystring in all pages in mvc

Question

I need to maintain the querystring in all pages in my asp.net mvc(C#) application.

For ex.: I will call a page www.example.com?Preview=True. The querystring should be maintained whatever the page i click in www.example.com. i.e. When i click About us page in www.example.com, the url should be www.example.com/AboutUs?Preview=True

How can i achieve this? Whats the best place to do this common operation.?

Answer 1

Maybe you need a custom route?:

public class PreviewRoute : System.Web.Routing.Route
{
    ...

    public override VirtualPathData GetVirtualPath(RequestContext requestContext, RouteValueDictionary values)
    {
        var preview = System.Web.HttpContext.Current.Session["Preview"];

        if (!values.ContainsKey("Preview"))
            values.Add("Preview", preview);

        var path = base.GetVirtualPath(requestContext, values);

        return path;
    }
}

}

Set Session["Preview"] at any time and you will get all your urls with ?Preview=True:

System.Web.HttpContext.Current.Session.Add("Preview", true);

UPDATED:

Use this route in the Global.asax.cs:

routes.Add("Default",
    new PreviewRoute("{controller}/{action}/{id}", new MvcRouteHandler()) {
        Defaults = new RouteValueDictionary(
            new { controller = "Home", action = "Index", id = "" }
        )
    }
);

instead of:

routes.MapRouteLowercase(
    "Default",                                              // Route name
    "{controller}/{action}/{id}",                           // URL with parameters
    new { controller = "Home", action = "Index", id = "" }  // Parameter defaults
);

Also you can try this extension:

public static class CustomRouteExtensions
{
    public static void MapPreviewRoute(this RouteCollection routes, string name, string url, object defaults) {
        routes.MapPreviewRoute(name, url, defaults, null);
    }

    public static void MapPreviewRoute(this RouteCollection routes, string name, string url, object defaults, object constraints) {
        if (routes == null) {
            throw new ArgumentNullException("routes");
        }

        if (url == null) {
            throw new ArgumentNullException("url");
        }

        var route = new PreviewRoute(url, new MvcRouteHandler()) {
            Defaults = new RouteValueDictionary(defaults),
            Constraints = new RouteValueDictionary(constraints)
        };

        if (String.IsNullOrEmpty(name)) {
            routes.Add(route);
        }
        else {
            routes.Add(name, route);
        }
    }
}

In Global.asax.cs:

routes.MapPreviewRoute(
    "Default",                                              // Route name
    "{controller}/{action}/{id}",                           // URL with parameters
    new { controller = "Home", action = "Index", id = "" }  // Parameter defaults
);