/// <summary>
        ///
        /// See base class
        ///
        /// </summary>
        /// <param name="caption"></param>
        /// <param name="message"></param>
        /// <param name="choices"></param>
        /// <param name="defaultChoice"></param>
        /// <returns></returns>
        /// <exception cref="ArgumentNullException">
        ///
        /// If <paramref name="choices"/> is null.
        ///
        /// </exception>
        /// <exception cref="ArgumentException">
        ///
        /// If <paramref name="choices"/>.Count is 0.
        ///
        /// </exception>
        /// <exception cref="ArgumentOutOfRangeException">
        ///
        /// If <paramref name="defaultChoice"/> is greater than
        ///     the length of <paramref name="choices"/>.
        ///
        /// </exception>
        /// <exception cref="PromptingException">
        ///
        ///  when prompt is canceled by, for example, Ctrl-c.
        ///
        /// </exception>

        public override int PromptForChoice(string caption, string message, Collection <ChoiceDescription> choices, int defaultChoice)
        {
            HandleThrowOnReadAndPrompt();

            if (choices == null)
            {
                throw new ArgumentNullException("choices");
            }

            if (choices.Count == 0)
            {
                throw new ArgumentException(Util.Sprintf(EmptyChoicesErrorTemplateResource, "choices"), "choices");
            }

            if ((defaultChoice < -1) || (defaultChoice >= choices.Count))
            {
                throw new ArgumentOutOfRangeException("defaultChoice", defaultChoice, Util.Sprintf(InvalidDefaultChoiceErrorTemplateResource, "defaultChoice", "choice"));
            }

            // we lock here so that multiple threads won't interleave the various reads and writes here.

            lock (_instanceLock)
            {
                if (!string.IsNullOrEmpty(caption))
                {
                    // Should be a skin lookup

                    WriteLineToConsole();
                    WriteToConsole(PromptColor, RawUI.BackgroundColor, WrapToCurrentWindowWidth(caption));
                    WriteLineToConsole();
                }

                if (!string.IsNullOrEmpty(message))
                {
                    WriteLineToConsole(WrapToCurrentWindowWidth(message));
                }

                int result = defaultChoice;

                string[,] hotkeysAndPlainLabels = null;
                HostUIHelperMethods.BuildHotkeysAndPlainLabels(choices, out hotkeysAndPlainLabels);

                Dictionary <int, bool> defaultChoiceKeys = new Dictionary <int, bool>();
                // add the default choice key only if it is valid. -1 is used to specify
                // no default.
                if (defaultChoice >= 0)
                {
                    defaultChoiceKeys.Add(defaultChoice, true);
                }

                do
                {
                    WriteChoicePrompt(hotkeysAndPlainLabels, defaultChoiceKeys, false);

                    ReadLineResult rlResult;
                    string         response = ReadLine(false, "", out rlResult, true, true);

                    if (rlResult == ReadLineResult.endedOnBreak)
                    {
                        string             msg = ConsoleHostUserInterfaceStrings.PromptCanceledError;
                        PromptingException e   = new PromptingException(
                            msg, null, "PromptForChoiceCanceled", ErrorCategory.OperationStopped);
                        throw e;
                    }

                    if (response.Length == 0)
                    {
                        // they just hit enter.

                        if (defaultChoice >= 0)
                        {
                            // if there's a default, pick that one.

                            result = defaultChoice;
                            break;
                        }

                        continue;
                    }

                    // decide which choice they made.

                    if (response.Trim() == "?")
                    {
                        // show the help

                        ShowChoiceHelp(choices, hotkeysAndPlainLabels);
                        continue;
                    }

                    result = HostUIHelperMethods.DetermineChoicePicked(response.Trim(), choices, hotkeysAndPlainLabels);

                    if (result >= 0)
                    {
                        break;
                    }

                    // their input matched none of the choices, so prompt again
                }while (true);

                return(result);
            }
        }
        /// <summary>
        /// Presents a dialog allowing the user to choose options from a set of options.
        /// </summary>
        /// <param name="caption">
        /// Caption to precede or title the prompt.  E.g. "Parameters for get-foo (instance 1 of 2)"
        /// </param>
        /// <param name="message">
        /// A message that describes what the choice is for.
        /// </param>
        /// <param name="choices">
        /// An Collection of ChoiceDescription objects that describe each choice.
        /// </param>
        /// <param name="defaultChoices">
        /// The index of the labels in the choices collection element to be presented to the user as
        /// the default choice(s).
        /// </param>
        /// <returns>
        /// The indices of the choice elements that corresponds to the options selected.
        /// </returns>
        /// <seealso cref="System.Management.Automation.Host.PSHostUserInterface.PromptForChoice"/>
        public Collection <int> PromptForChoice(string caption,
                                                string message,
                                                Collection <ChoiceDescription> choices,
                                                IEnumerable <int> defaultChoices)
        {
            HandleThrowOnReadAndPrompt();

            if (choices == null)
            {
                throw new ArgumentNullException("choices");
            }

            if (choices.Count == 0)
            {
                throw new ArgumentException(Util.Sprintf(EmptyChoicesErrorTemplateResource, "choices"), "choices");
            }

            Dictionary <int, bool> defaultChoiceKeys = new Dictionary <int, bool>();

            if (null != defaultChoices)
            {
                foreach (int defaultChoice in defaultChoices)
                {
                    if ((defaultChoice < 0) || (defaultChoice >= choices.Count))
                    {
                        throw new ArgumentOutOfRangeException(
                                  "defaultChoice",
                                  defaultChoice,
                                  Util.Sprintf("\"{0}\" must be a valid index into \"{1}\". \"{2}\" is not a valid index.",
                                               "defaultChoice",
                                               "choices",
                                               defaultChoice));
                    }

                    if (!defaultChoiceKeys.ContainsKey(defaultChoice))
                    {
                        defaultChoiceKeys.Add(defaultChoice, true);
                    }
                }
            }

            Collection <int> result = new Collection <int>();

            // we lock here so that multiple threads won't interleave the various reads and writes here.
            lock (_instanceLock)
            {
                // write caption on the console, if present.
                if (!string.IsNullOrEmpty(caption))
                {
                    // Should be a skin lookup
                    WriteLineToConsole();
                    WriteToConsole(PromptColor, RawUI.BackgroundColor, WrapToCurrentWindowWidth(caption));
                    WriteLineToConsole();
                }
                // write message
                if (!string.IsNullOrEmpty(message))
                {
                    WriteLineToConsole(WrapToCurrentWindowWidth(message));
                }

                string[,] hotkeysAndPlainLabels = null;
                HostUIHelperMethods.BuildHotkeysAndPlainLabels(choices, out hotkeysAndPlainLabels);

                WriteChoicePrompt(hotkeysAndPlainLabels, defaultChoiceKeys, true);
                if (defaultChoiceKeys.Count > 0)
                {
                    WriteLineToConsole();
                }

                // used to display ChoiceMessage like Choice[0],Choice[1] etc
                int choicesSelected = 0;
                do
                {
                    // write the current prompt
                    string choiceMsg = Util.Sprintf(ConsoleHostUserInterfaceStrings.ChoiceMessage, choicesSelected);
                    WriteToConsole(PromptColor, RawUI.BackgroundColor, WrapToCurrentWindowWidth(choiceMsg));

                    ReadLineResult rlResult;
                    string         response = ReadLine(false, "", out rlResult, true, true);

                    if (rlResult == ReadLineResult.endedOnBreak)
                    {
                        string             msg = ConsoleHostUserInterfaceStrings.PromptCanceledError;
                        PromptingException e   = new PromptingException(
                            msg, null, "PromptForChoiceCanceled", ErrorCategory.OperationStopped);
                        throw e;
                    }

                    // they just hit enter
                    if (response.Length == 0)
                    {
                        // this may happen when
                        // 1. user wants to go with the defaults
                        // 2. user selected some choices and wanted those
                        // choices to be picked.

                        // user did not pick up any choices..choose the default
                        if ((result.Count == 0) && (defaultChoiceKeys.Keys.Count >= 0))
                        {
                            // if there's a default, pick that one.
                            foreach (int defaultChoice in defaultChoiceKeys.Keys)
                            {
                                result.Add(defaultChoice);
                            }
                        }
                        // allow for no choice selection.
                        break;
                    }

                    // decide which choice they made.
                    if (response.Trim() == "?")
                    {
                        // show the help
                        ShowChoiceHelp(choices, hotkeysAndPlainLabels);
                        continue;
                    }

                    int choicePicked = HostUIHelperMethods.DetermineChoicePicked(response.Trim(), choices, hotkeysAndPlainLabels);

                    if (choicePicked >= 0)
                    {
                        result.Add(choicePicked);
                        choicesSelected++;
                    }
                    // prompt for multiple choices
                }while (true);

                return(result);
            }
        }