How does Outlook insert "magic" addresses into To field?

How do Outlook's TextBox objects intelligently know that contact information has been added and that it corresponds to existing ContactItems?

How can I duplicate this beh开发者_StackOverflowavior for a custom form region using C#?

private void FooButton_Click(object sender, EventArgs e) {
    Outlook.Application Application = new Outlook.Application();
    // Add ListView's selected items to BarTextBox
}