WebFromsAndSRP

Default.aspx.cs

using System;
using WebFormsAndSRP.CookieManagement;

namespace WebFormsAndSRP
{
    public partial class Default : System.Web.UI.Page
    {
        private IMarketingTracker _marketingTracker;
        protected void Page_Load(object sender, EventArgs e)
        {
            _marketingTracker = new MarketingTrackerBuilder(Request.Cookies).Build();
        }

        protected void OnSaveButtonClick(object sender, EventArgs e)
        {
            Db.SaveEnquiry(_marketingTracker);
        }
    }

    public static class Db
    {
        public static void SaveEnquiry(IMarketingTracker marketingTracker)
        {
            // Do some Db stuff
        }
    }
}

MaketingTrackerBuilder.cs

namespace WebFormsAndSRP.CookieManagement
{
    public class MarketingTrackerBuilder
    {
        private readonly HttpCookie _cookie;
        private const string CookieName = "campaigns";
        private readonly Dictionary<string,string> _values;
        
        public MarketingTrackerBuilder(HttpCookieCollection cookieCollection)
        {
            _cookie = cookieCollection[CookieName];
            _values = new Dictionary<string, string>();
        }

        private void SplitCookie()
        {
            var values = _cookie.Value.Split(',');
            foreach (var item in values.Select(value => value.Split('=')))
            {
                _values.Add(item[0], item[1]);
            }
        }

        private string Value(string key)
        {
            string output;
            return _values.TryGetValue(key, out output) ? output : string.Empty;
        }

        public IMarketingTracker Build()
        {
            if (_cookie == null) return new NullMarketingTracker();
            
            SplitCookie();

            return new MarketingTracker(Value("ch"),Value("ca"),Value("ta"),Value("de"));
        }
    }
}

MarketingTracker.cs

namespace WebFormsAndSRP.CookieManagement
{
    public interface IMarketingTracker
    {
        string Channel { get; }
        string Campaign { get; }
        string Target { get; }
        string Detail { get; }
    }

    public class MarketingTracker : IMarketingTracker
    {
        public string Channel { get; private set; }
        public string Campaign { get; private set; }
        public string Target { get; private set; }
        public string Detail { get; private set; }

        public MarketingTracker(string channel, string campaign, string target, string detaill)
        {
            Channel = channel;
            Campaign = campaign;
            Target = target;
            Detail = detaill;
        }
    }
}

NullMarketingTracker.cs

namespace WebFormsAndSRP.CookieManagement
{
    public class NullMarketingTracker : IMarketingTracker
    {
        public string Channel
        {
            get { return string.Empty; }
        }

        public string Campaign
        {
            get { return string.Empty; }
        }

        public string Target
        {
            get { return string.Empty; }
        }

        public string Detail
        {
            get { return string.Empty; }
        }
    }
}

ViolatesSRP.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.UI;

namespace WebFormsAndSRP
{
    public partial class ViolatesSRP : Page
    {
        private Dictionary<string, string> _values = new Dictionary<string, string>();

        protected void Page_Load(object sender, EventArgs e)
        {
            var cookie = Request.Cookies["campaign"];

            if (cookie == null || String.IsNullOrEmpty(cookie.Value)) return;
            

            var items = cookie.Value.Split(',');
            _values = items.Select(value => value.Split('='))
                .ToDictionary(item => item[0], item => item[1]);


        }

        protected void OnSaveButtonClick(object sender, EventArgs e)
        {
            Db.SaveEnquiry(Value("ch"), Value("ca"), Value("ta"), Value("de"));
        }

        private string Value(string key)
        {
            string output;
            return _values.TryGetValue(key, out output) ? output : string.Empty;
        }
    }

    public static class Db
    {
        public static void SaveEnquiry(string channel, string campaign, string target, string detail)
        {
            
        }
    }
}