C#

chart1.Series["CAR"].ToolTip = "Year: #VALX  MarketValue: #VALY" 

Dictionary<int,string> D = new Dictionary<int,string>();
D.Add(1982,"Cinquecento");
D.Add(2000,"Espace");

chart1.Series["CAR"].ToolTip = "Year: #VALX  MarketValue: #VALY Model: " 
// here I need to get the model from dictionary associed to the year (#VALX) and add it

public class MeinPaketRequest
    {
        public string TestURL { get; set; }
        public string URL { get; set; }
        public string Username { get; set; }
        public string Password { get; set; }
        public bool Test { get; set; }
        CookieContainer _cookies = new CookieContainer();


        public MeinPaketRequest()
        {
            this.TestURL = "https://mp-api.mepa-home.de/dealerapi/xml";
            this.URL = "https://www.meinpaket.de/dealerapi/xml";
            this.Test = true;
            this.Username = "Username";
            this.Password = "Password";
        }

        public string Request(string Filename)
        {
            if (string.IsNullOrWhiteSpace(Filename))
            {
                Filename = "C:\\Users\\TWGT-KASSE-2\\Desktop\\MeinPaket\\Beispieldateien_042013\\mp_example_30_01_download_orders.xml";
            }

            XmlDocument xDocument = new XmlDocument();
            xDocument.Load(Filename);

            foreach (XmlNode oNode in xDocument.ChildNodes)
            {
                if (oNode.Name == "dataRequest")
                {
                    foreach (XmlNode oNodeRequest in oNode.ChildNodes)
                    {
                        if (oNodeRequest.Name == "header")
                        {
                            foreach (XmlNode oNodeHeader in oNodeRequest.ChildNodes)
                            {

                                if (oNodeHeader.Name == "password")
                                    oNodeHeader.InnerText = this.Password;
                                
                                if (oNodeHeader.Name == "login")
                                    oNodeHeader.InnerText = this.Username;

                            }
                        }
                    }
                }
            }


            // Leerer WebRequest
            HttpWebRequest oWebRequest = null;

            if (this.Test)
            {
                // im Testbetrieb die Test URL nutzen
                oWebRequest = (HttpWebRequest)WebRequest.Create(this.TestURL);
            }
            else
            {
                // im LiveBetrieb die Live-URL nutzen
                oWebRequest = (HttpWebRequest)WebRequest.Create(this.URL);
            }

            // Test settings
            oWebRequest.CookieContainer = _cookies;
            oWebRequest.Accept = "*/*";
            oWebRequest.KeepAlive = true;
            oWebRequest.UseDefaultCredentials = true;
            oWebRequest.UserAgent = "Mozilla/5.0";
            oWebRequest.PreAuthenticate = true;
            

            // Credentials mit Username / Passwort erstellen
            oWebRequest.Credentials = new NetworkCredential(this.Username, this.Password);

            // ContentType ist Text/XML
            oWebRequest.ContentType = "text/xml";

            // Method ist POST
            oWebRequest.Method = "POST";

            // Encoding für den Inhalt ist UTF-8
            byte[] bytes = Encoding.UTF8.GetBytes(xDocument.InnerXml.ToString());

            // Länge des Request messen
            oWebRequest.ContentLength = bytes.Length;

            // Stream an MeinPaket übertragen
            using (Stream oStream = oWebRequest.GetRequestStream())
            {
                oStream.Write(bytes, 0, bytes.Length);
            }

            // Antwort von MeinPaket abholen
            using (WebResponse oWebResponse = oWebRequest.GetResponse())
            {
                // ohne Antwort kann nix zurückgegeben werden
                if (oWebResponse == null)
                    return null;

                // Antwort lesen
                using (StreamReader oStreamReader = new StreamReader(oWebResponse.GetResponseStream()))
                {
                    // Antwort zurückgeben
                    return oStreamReader.ReadToEnd().Trim();
                }
            }
        }

    }