private void LoadPlanetList()
        {
            if (this.comboBoxPlanetList.InvokeRequired)
            {
                MessageBox.Show("invoke required");
            }
            else
            {
                comboBoxPlanetList.ValueMember = "Key";
                comboBoxPlanetList.DisplayMember = "Value";
                comboBoxPlanetList.DataSource = new BindingSource(PlanetList, null);
            }
        }
//this line causes a threading error without the if statement.
comboBoxPlanetList.ValueMember = "Key";
fi