问如何调用Guide.BeginShowMessageBox

EN

public object FuelTypeIndex { get; private set; }

private void PhoneApplicationPage_Loaded(object sender, RoutedEventArgs e)
{
    var messageCommands = new Dictionary<string, Action>()
    {
        {  "Diesel", () => {FuelTypeIndex = 0;}},
        {  "Petrol", () => {FuelTypeIndex = 1;}},
        {  "Other", () => {FuelTypeIndex = 2;}},
    };

    var result = Guide.BeginShowMessageBox("Title", "Message", messageCommands.Keys, 0, MessageBoxIcon.Warning, null, null);
    result.AsyncWaitHandle.WaitOne();

    int? choice = Guide.EndShowMessageBox(result);
    if (choice.HasValue)
        messageCommands.ElementAt(choice.Value).Value.Invoke();
}