class Planet
    {
        private string myName;
        private double myGravitationalAcceleration;
 
        public Planet(string strName, double Acceleration)
        {
            this.myName = strName;
            this.myGravitationalAcceleration = Acceleration;
        }
 
        public string Name
        {
            get
            {
                return myName;
            }
        }
 
        public double GravitationalAcceleration
        {
            get
            {
                return myGravitationalAcceleration;
            }
        }
    }

public partial class InputData : Form
    {
        public InputData()
        {
            InitializeComponent();
            List<Planet> Planets = new List<Planet>();
            Planets.Add(new Planet("Earth at equator 0°", 9.78));           
            Planets.Add(new Planet("Earth at equinox 23.5°", 9.788));
            Planets.Add(new Planet("Earth at lattitude 50°", 9.81));
            Planets.Add(new Planet("Earth at pole 90°", 9.83));
            Planets.Add(new Planet("Moon", 1.63));
            Planets.Add(new Planet("Mars", 3.69));
            Planets.Add(new Planet("Venus", 8.87));
            Planets.Add(new Planet("Titan", 1.352));
            GraviAccelCombo.DataSource = Planets;
            //add names of properties here, seems cool!
            GraviAccelCombo.DisplayMember = "Name";
            GraviAccelCombo.ValueMember = "GravitationalAcceleration";
 
        }
 
        //private void GraviAccelCombo_SelectedIndexChanged(object sender, EventArgs e)
        //{
        //    GraviAccelCombo.Text = GraviAccelCombo.SelectedValue.ToString();
        //}
 
        private void GraviAccelCombo_SelectedValueChanged(object sender, EventArgs e)
        {
            if (GraviAccelCombo.SelectedIndex != -1)
            {
                GraviAccelCombo.Text = GraviAccelCombo.SelectedValue.ToString();
            }
        }
    }

    private void comboBox1_DropDown(object sender, EventArgs e)
    {
      comboBox1.DisplayMember = "Name";
    }
 
    private void comboBox1_DropDownClosed(object sender, EventArgs e)
    {
      comboBox1.DisplayMember = "GravitationalAcceleration";
    }