Adds prompt tree

examples/Console/Prompt/Program.cs

@@ -1,3 +1,5 @@
+using System.Collections.Generic;
+using System.Linq;
 using Spectre.Console;
 
 namespace Prompt
@@ -26,6 +28,9 @@ public static void Main(string[] args)
  WriteDivider("Lists");
  var fruit = AskFruit();
 
+ WriteDivider("Prompt Tree");
+ var deepSpaceObjects = AskDeepSpaceObjects();
+
  WriteDivider("Choices");
  var sport = AskSport();
 
@@ -52,6 +57,7 @@ public static void Main(string[] args)
  .BorderColor(Color.Grey)
  .AddRow("[grey]Name[/]", name)
  .AddRow("[grey]Favorite fruit[/]", fruit)
+ .AddRow("[grey]Favorite DSOs[/]", string.Join(", ", deepSpaceObjects))
  .AddRow("[grey]Favorite sport[/]", sport)
  .AddRow("[grey]Age[/]", age.ToString())
  .AddRow("[grey]Password[/]", password)
@@ -119,6 +125,62 @@ public static string AskFruit()
  return fruit;
  }
 
+ public static IEnumerable<string> AskDeepSpaceObjects()
+ {
+ var tree =
+ new SelectableItems(
+ "All",
+ new SelectableItems(
+ "Galaxies",
+ new SelectableItems(
+ "Spiral",
+ new SelectableItem("Milky Way"),
+ new SelectableItem("M31 (Andromeda)")),
+ new SelectableItems(
+ "Elliptical",
+ new SelectableItems("M87 (Virgo A)"),
+ new SelectableItems("M49 (NGC 4472)"))),
+ new SelectableItems(
+ "Globular Clusters",
+ new SelectableItem("NGC 5139 (Omega Centauri)"),
+ new SelectableItem("M13 (Hercules)"),
+ new SelectableItem("M3"),
+ new SelectableItem("M5")),
+ new SelectableItems(
+ "Open Clusters",
+ new SelectableItem("M45 (The Pleiades)"),
+ new SelectableItem("M44 (The Beehive Cluster)"),
+ new SelectableItem("M6 (the Butterfly Cluster)"),
+ new SelectableItem("M7 (Ptolemy's Cluster)")),
+ new SelectableItems(
+ "Nebulas",
+ new SelectableItems(
+ "Emission",
+ new SelectableItem("M42 (Orion Nebula)"),
+ new SelectableItem("M16 (Eagle Nebula)")),
+ new SelectableItems(
+ "Planetary",
+ new SelectableItem("M57 (Ring Nebula)"),
+ new SelectableItem("M27 (Dumbbell Nebula)"))));
+
+ return AnsiConsole.Prompt(
+ new MultiSelectionPrompt<SelectableItem>()
+ .AddChoiceTree(
+ tree,
+ selectableItem =>
+ selectableItem is SelectableItems selectableItems
+ ? selectableItems.Children
+ : Enumerable.Empty<SelectableItem>())
+ .PageSize(15)
+ .Title("What are your favorite DSOs?")
+ .HighlightStyle(
+ new Style(
+ Color.Black,
+ Color.SteelBlue1))
+ .UseConverter(selectable => selectable.Name))
+ .Select(selectableItem => selectableItem.Name);
+ }
+
  public static string AskSport()
  {
  return AnsiConsole.Prompt(

examples/Console/Prompt/SelectableItem.cs

@@ -0,0 +1,25 @@
+using System.Collections.Generic;
+
+namespace Prompt
+{
+ internal class SelectableItem
+ {
+ public string Name { get; set; }
+
+ public SelectableItem(string name)
+ {
+ Name = name;
+ }
+ }
+
+ internal class SelectableItems : SelectableItem
+ {
+ public IEnumerable<SelectableItem> Children { get; set; }
+
+ public SelectableItems(string name, params SelectableItem[] children) :
+ base(name)
+ {
+ Children = children;
+ }
+ }
+}

src/Spectre.Console/Prompts/MultiSelectionPromptExtensions.cs

@@ -147,6 +147,46 @@ public static MultiSelectionPrompt<T> AddChoiceGroup<T>(this MultiSelectionPromp
  return obj;
  }
 
+ /// <summary>
+ /// Adds choice tree.
+ /// </summary>
+ /// <typeparam name="T">The prompt result type.</typeparam>
+ /// <param name="obj">The prompt.</param>
+ /// <param name="rootChoice">The tree's root.</param>
+ /// <param name="getChildChoices">A function to get node child choices.</param>
+ /// <returns>The same instance so that multiple calls can be chained.</returns>
+ public static MultiSelectionPrompt<T> AddChoiceTree<T>(this MultiSelectionPrompt<T> obj, T rootChoice, Func<T, IEnumerable<T>> getChildChoices)
+ where T : notnull
+ {
+ var multiSelectionItem = obj.AddChoice(rootChoice);
+ AddChildChoice(
+ getChildChoices,
+ rootChoice,
+ multiSelectionItem,
+ rootChoice: true);
+ return obj;
+
+ static void AddChildChoice(
+ Func<T, IEnumerable<T>> getChildChoices,
+ T parentChoice,
+ ISelectionItem<T> selectionItem,
+ bool rootChoice = false)
+ {
+ if (!rootChoice)
+ {
+ selectionItem = selectionItem.AddChild(parentChoice);
+ }
+
+ foreach (var childChoice in getChildChoices(parentChoice))
+ {
+ AddChildChoice(
+ getChildChoices,
+ childChoice,
+ selectionItem);
+ }
+ }
+ }
+
  /// <summary>
  /// Marks an item as selected.
  /// </summary>