class SliderListener : IDisposable
        {
            private IGH_Component owner;
            Guid currentId;
            List<Grasshopper.Kernel.Special.GH_NumberSlider> Sliders;
            string slavePrefix;
            string masterPrefix;
            bool enabled = true;
            /// <summary>
            ///  This class takes care of all the wizardry involved in events inside a C# block, especially the part where we need to self-destruct,
            ///  or a C# block gets copied, recompiled or other stuff that creates indestructable event listeners.
            /// </summary>
            /// <param name="owner">The GH_Component that is the owner of this listener. If this gets modified or is locked, we'll inititate a self destruct sequence.</param>
            /// <param name="masterPrefix">We'll catch on to the sliders that start with this prefix</param>
            /// <param name="slavePrefix">We'll look for slaves that are equal to the master's name, except the prefix is different</param>
            /// <param name="debug">Should we talk to you through the Rhino command line?</param>
            public SliderListener (IGH_Component owner, string masterPrefix, string slavePrefix, bool debug)
            {
                this.owner = owner;
                this.currentId = Guid.NewGuid();
                owner.Message = currentId.ToString();
                this.debug = debug;
                this.slavePrefix = slavePrefix;
                this.masterPrefix = masterPrefix;
                this.Sliders = FindSlidersThatStartWithName(masterPrefix);
                if (slavePrefix.Length < 4 || masterPrefix.Length < 4)
                {
                    throw new Exception("Please use a prefix longer than x");
                }

                Debug("Found " + Sliders.Count + " sliders");
                foreach (var slider in this.Sliders)
                {
                    slider.SolutionExpired += Callback;
                }

                this.owner.ObjectChanged += CheckStillValid;
            }

            void CheckStillValid(IGH_DocumentObject sender, GH_ObjectChangedEventArgs e)
            {
                if (!IsValid())
                {
                    this.Dispose();
                }
            }

            public Func<Grasshopper.Kernel.Special.GH_NumberSlider, Grasshopper.Kernel.Special.GH_NumberSlider, bool> CustomCallback;

            public bool IsValid ()
            {
                return !(!enabled || this.owner == null || this.owner.OnPingDocument() == null
                    || this.owner.Locked || !this.owner.Message.Equals(this.currentId.ToString()));
            }

            private void Debug(string message)
            {
                if (this.debug)
                {
                    RhinoApp.WriteLine(message);
                }
            }

            private void Callback(IGH_DocumentObject sender, GH_SolutionExpiredEventArgs e)
            {
                Debug("Hello from the slider callback!");
                var slider = sender as Grasshopper.Kernel.Special.GH_NumberSlider;
                if (slider == null || !this.IsValid())
                {
                    // ok, we're out of here, let's get rid of all the slaves.
                    this.Dispose();
                    return;
                }

                var slaves = FindSlavesByNameOfMaster(sender.NickName);
                Debug("Found " + slaves.Count + " slaves");
                foreach (var slave in slaves)
                {
                    if (CustomCallback != null)
                    {
                        bool test = CustomCallback(slider, slave);
                    }
                }
            }

            public void Dispose()
            {
                Debug("Disposing the slider listener2");
                // just in case someone keeps hanging on to this class after we've called dispose.
                enabled = false;
                foreach (var numberSlider in Sliders)
                {
                    numberSlider.SolutionExpired -= this.Callback;
                }
                if (this.owner != null)
                {
                    owner.ObjectChanged -= CheckStillValid;
                }
            }

            private List<Grasshopper.Kernel.Special.GH_NumberSlider> FindSlidersThatStartWithName(string name)
            {
                return this.owner.OnPingDocument()
                    .Objects
                    .OfType<Grasshopper.Kernel.Special.GH_NumberSlider>()
                    .Where(obj => obj.NickName.StartsWith(name))
                    .ToList();
            }


            private List<Grasshopper.Kernel.Special.GH_NumberSlider> FindSlavesByNameOfMaster(string mastersName)
            {

                string slave = mastersName.Replace(this.masterPrefix, this.slavePrefix);

                if (slave.Equals(mastersName))
                {
                    // something went wrong, and the master's name is no longer a master's name.
                    // a slider should not control itself.
                    return new List<Grasshopper.Kernel.Special.GH_NumberSlider>();
                }

                return this.owner.OnPingDocument()
                    .Objects
                    .OfType<Grasshopper.Kernel.Special.GH_NumberSlider>()
                    .Where(obj => obj.NickName.Equals(slave))
                    .ToList();
            }

            public bool debug { get; set; }
        }

}