Event for Change of Input Parameter Value C#

Hi guys, 

Is there an Event to detect if the value of an input parameter has changed? 
I tried Component.Params.ParameterChanged which is working if another component is connected, but not if the value is changed. 

This is what I am trying to achieve: If the dropdown component is changed, the c#-component should update the slider...
It is also working with GH_Document.SolutionEnd Event but as far as I understand, this will recompute the whole solution. So if there is a huge script following downstream, this will be called always twice (correct?). 
I would like the script to:

1. detected the change of an input parameter value
2. stop the script and set a few sliders
3. continue computing downstream stuff.

Thanks in advance!

private void RunScript(System.Object mySliders, bool startme, ref object A)
{
    if (!startme)
    return;

    if (_running)
        return;

    _run = true;

    Component.Params.ParameterChanged += new                   GH_ComponentParamServer.ParameterChangedEventHandler(OnSolutionEnd);

}

// <Custom additional code>
private bool _run = false;
private bool _running = false;

private void OnSolutionEnd(object sender, GH_ParamServerEventArgs e)
{
    // Unregister the event, we don't want to get called again.
    Component.Params.ParameterChanged -= OnSolutionEnd;

    // If we're not supposed to run, abort now.
    if (!_run)
        return;

    // If we're already running, abort now.
        if (_running)
        return;

    // Reset run and running states.
    _run = false;
    _running = true;

    foreach (IGH_DocumentObject obj in GrasshopperDocument.Objects)
    {
        if(obj is Grasshopper.Kernel.Special.GH_NumberSlider)
        {
            var slider = obj as Grasshopper.Kernel.Special.GH_NumberSlider;
            slider.TickValue = 9;
            _running = false;
         }
    }
}