/// <summary>
/// Provides a set of choices that enable the user to choose a one or more options
/// from a set of options.
/// </summary>
/// <param name="caption">A title that proceeds the choices.</param>
/// <param name="message">
/// An introduction message that describes the
/// choices.
/// </param>
/// <param name="choices">A collection of ChoiceDescription objects that describe each choice.</param>
/// <param name="defaultChoices">
/// The index of the label in the Choices parameter
/// collection that indicates the default choice used if the user does not specify
/// a choice. To indicate no default choice, set to -1.
/// </param>
/// <returns>
/// The index of the Choices parameter collection element that corresponds
/// to the choices selected by the user.
/// </returns>
public Collection <int> PromptForChoice(
string caption,
string message,
Collection <ChoiceDescription> choices,
IEnumerable <int> defaultChoices)
{
// Write the caption and message strings in Blue.
WriteLine(
RawUI.ForegroundColor,
RawUI.BackgroundColor,
caption + "\n" + message + "\n");
// Convert the choice collection into something that's a
// little easier to work with
// See the BuildHotkeysAndPlainLabels method for details.
var promptData = BuildHotkeysAndPlainLabels(choices);
// Format the overall choice prompt string to display...
var sb = new StringBuilder();
for (var element = 0; element < choices.Count; element++)
{
sb.Append(string.Format(
CultureInfo.CurrentCulture,
"|{0}> {1} ",
promptData[0, element],
promptData[1, element]));
}
var defaultResults = new Collection <int>();
if (defaultChoices != null)
{
var countDefaults = 0;
var enumerable = defaultChoices as int[] ?? defaultChoices.ToArray();
foreach (var defaultChoice in enumerable)
{
++countDefaults;
defaultResults.Add(defaultChoice);
}
if (countDefaults != 0)
{
sb.Append(countDefaults == 1 ? "[Default choice is " : "[Default choices are ");
foreach (var defaultChoice in enumerable)
{
sb.AppendFormat(
CultureInfo.CurrentCulture,
"\"{0}\",",
promptData[0, defaultChoice]);
}
sb.Remove(sb.Length - 1, 1);
sb.Append("]");
}
}
WriteLine(RawUI.ForegroundColor, RawUI.BackgroundColor, sb.ToString());
// loop reading prompts until a match is made, the default is
// chosen or the loop is interrupted with ctrl-C.
var results = new Collection <int>();
while (true)
{
ReadNext:
var prompt = string.Format(CultureInfo.CurrentCulture, "Choice[{0}]:", results.Count);
Write(RawUI.ForegroundColor, RawUI.BackgroundColor, prompt);
var data = _debugger.ReadLine().Trim().ToUpper(CultureInfo.CurrentCulture);
// if the choice string was empty, no more choices have been made.
// if there were no choices made, return the defaults
if (data.Length == 0)
{
return(results.Count == 0 ? defaultResults : results);
}
// see if the selection matched and return the
// corresponding index if it did...
for (var i = 0; i < choices.Count; i++)
{
if (promptData[0, i] == data)
{
results.Add(i);
goto ReadNext;
}
}
WriteErrorLine("Invalid choice: " + data);
}
}
