Actually I tried this out and its a bit harder than I thought... anyway I've got something that should work for you, hopefully you can understand it and modify it to your needs. Let me know if you get stuck!
Code:
public Form1()
{
InitializeComponent();
DataTable dt = new DataTable();
dt.Columns.Add("Result", typeof(string));
dt.Columns.Add("Points", typeof(string));
dt.Rows.Add(new string[]{"Win", "3 points"});
dt.Rows.Add(new string[] { "Lose", "0 points" });
dt.Rows.Add(new string[] { "Draw", "1 points" });
dt.Rows.Add(new string[] { "Cancelled", "0 points" });
this.comboBox1.DropDown += new System.EventHandler(this.comboBox1_DropDown);
this.comboBox1.SelectedIndexChanged += new System.EventHandler(this.comboBox1_SelectedIndexChanged);
comboBox1.DataSource = dt;
comboBox1.DisplayMember = "Points";
}
private void comboBox1_DropDown(object sender, EventArgs e)
{
comboBox1.DisplayMember = "Result";
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
int nSel = comboBox1.SelectedIndex;
comboBox1.DisplayMember = "Points";
comboBox1.SelectedIndex = nSel;
}