Converting any object to a RouteValueDictionary so I don’t have to list properties in a MVC view

Problem

The problem I had is that I had a search page, which went to a search results page that could be paginated. The paginator needs to know the search criteria used, so it can create a link on the page which calls for page x with the correct search criteria set.

I originally had code that looked like this in my view:

    @Html.PageLinks(Model.PagingInfo, x => Url.Action("Search",
        new
        {
            shortName = Model.SearchCriteria.ShortName,
            soundsLike = Model.SearchCriteria.SoundsLike,
            postCode = Model.SearchCriteria.PostCode,
            policyNumber = Model.SearchCriteria.PolicyNumber,
            previousVersions = Model.SearchCriteria.PreviousVersions,
            page = x
        }))

The search criteria class has a list of properties that can be searched for. The problem is, I didn’t want to have a list of all the properties in any views that use it, I wanted to be able to say:

    @Html.PageLinks(Model.PagingInfo, x => Url.Action("Search",
        new
        {
            searchCriteria = Model.SearchCriteria.ShortName,
            page = x
        }))

However this code does not work, as you can’t pass a complex object into Url.Action. Serialising this into a query string doesn’t work. I looked into how I could do this via fixing the serialisation problem, but chose a different approach in the end which is documented below.

One Solution

Url.Action can take an anonymous object, or it can take a RouteValueDictionary. So the first step was to put a ToRouteValueDictionary in my model. This wasn’t going to work for me, because my domain classes don’t access System.Web (or any data access routines for that matter, I use IOC).

So I decided on an extension method that used reflection to create a Dictionary, this only adds results if the value isn’t null, which means we don’t have lots of null querystring parameters in practice:

using System;
using System.Collections.Generic;
using System.ComponentModel;

namespace Ncs.Ida.Common.ExtensionMethods
{
    public static class ToDictionaryExtensionMethod
    {
        public static IDictionary ToDictionary(this object source)
        {
            return source.ToDictionary