Better URL binding in WebAPI

gistfile1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Web;
using System.Web.Http.Controllers;
using System.Web.Http.Filters;

public class UrlBindingAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(HttpActionContext actionContext)
    {
        if (actionContext.ActionArguments.Count == 0)
        {
            return;
        }

        var model = GetOrInitializeModel(actionContext);

        BindPropertiesFromUrl(actionContext, model);
    }

    private static void BindPropertiesFromUrl(HttpActionContext actionContext, object model)
    {
        var modelType = model.GetType();
        var routeParams = actionContext.ControllerContext.RouteData.Values;
        var queryString = HttpUtility.ParseQueryString(actionContext.Request.RequestUri.Query);

        MapUrlParams(model, modelType, routeParams);
        MapUrlParams(model, modelType, queryString.AllKeys.Select(k => new KeyValuePair<string, object>(k, queryString[k])));
    }

    private static void MapUrlParams(object model, Type modelType, IEnumerable<KeyValuePair<string, object>> routeParams)
    {
        foreach (var nameValue in routeParams.Where(k => !string.IsNullOrEmpty(k.Key) && k.Key != "controller"))
        {
            var prop = modelType.GetProperty(nameValue.Key, BindingFlags.IgnoreCase | BindingFlags.Instance | BindingFlags.Public);
            if (prop != null)
            {
                if (prop.PropertyType.IsArray)
                {
                    SetArrayProperty(model, prop, nameValue.Value);
                }
                else
                {
                    SetPlainProperty(model, prop, nameValue.Value);
                }
            }
        }
    }

    private static void SetPlainProperty(object model, PropertyInfo prop, object val)
    {
        var descriptor = TypeDescriptor.GetConverter(prop.PropertyType);
        if (descriptor.CanConvertFrom(typeof(string)))
        {
            prop.SetValueFast(model, descriptor.ConvertFromString(null, CultureInfo.InvariantCulture, val as string));
        }            
    }

    private static void SetArrayProperty(object model, PropertyInfo prop, object val)
    {
        var stringVals = val.ToString().Split(',');
        var elementType = prop.PropertyType.GetElementType();
        var descriptor = TypeDescriptor.GetConverter(elementType);

        if (descriptor.CanConvertFrom(typeof(string)))
        {
            var arr = Array.CreateInstance(elementType, stringVals.Length);
            for (var i = 0; i < stringVals.Length; ++i)
            {
                arr.SetValue(descriptor.ConvertFromString(stringVals[i].Trim()), i);
            }

            prop.SetValueFast(model, arr);
        }
    }

    private static object GetOrInitializeModel(HttpActionContext actionContext)
    {
        var model = actionContext.ActionArguments.Values.First();
        if (model == null)
        {
            actionContext.ActionArguments[actionContext.ActionArguments.Keys.First()] = model = Activator.CreateInstance(actionContext.ActionDescriptor.ActionBinding.ParameterBindings[0].Descriptor.ParameterType);
        }
        return model;
    }
}