Terminal.Gui/UICatalog/Scenarios/InteractiveTree.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Terminal.Gui;
using static UICatalog.Scenario;

namespace UICatalog.Scenarios {

	[ScenarioMetadata (Name: "Interactive Tree", Description: "Create nodes and child nodes in TreeView")]
	[ScenarioCategory ("Controls")]
	class InteractiveTree : Scenario{

		TreeView treeView;

		public override void Setup ()
		{
			Win.Title = this.GetName();
			Win.Y = 1; // menu
			Win.Height = Dim.Fill (1); // status bar
			Top.LayoutSubviews ();
			
			var menu = new MenuBar (new MenuBarItem [] {
				new MenuBarItem ("_File", new MenuItem [] {
					new MenuItem ("_Quit", "", () => Quit()),
				}) 
				});
			
			treeView = new TreeView() {
				X = 0,
				Y = 0,
				Width = Dim.Fill(),
				Height = Dim.Fill(1),
			};
			treeView.KeyPress += TreeView_KeyPress;
			
			Win.Add(treeView);

			var statusBar = new StatusBar (new StatusItem [] {
				new StatusItem(Key.CtrlMask | Key.Q, "~^Q~ Quit", () => Quit()),
				new StatusItem(Key.CtrlMask | Key.C, "~^C~ Add Child", () => AddChildNode()),
				new StatusItem(Key.CtrlMask | Key.T, "~^T~ Add Root", () => AddRootNode()),
				new StatusItem(Key.CtrlMask | Key.R, "~^R~ Rename Node", () => RenameNode()),
			});
			Top.Add (statusBar);

		}

		private void TreeView_KeyPress (View.KeyEventEventArgs obj)
		{
			if(obj.KeyEvent.Key == Key.DeleteChar) {

				var toDelete = treeView.SelectedObject;

				if(toDelete == null)
					return;
				
				obj.Handled = true;

				// if it is a root object remove it
				if(treeView.Objects.Contains(toDelete)) {
					treeView.Remove(toDelete);
				}
				else {
					var parent = treeView.GetParent(toDelete);

					if(parent == null)
						MessageBox.ErrorQuery("Could not delete",$"Parent of '{toDelete}' was unexpectedly null","Ok");
					else {
						//update the model
						parent.Children.Remove(toDelete);

						//refresh the tree
						treeView.RefreshObject(parent);
					}
				}
			}
		}

		private void RenameNode ()
		{
			var node = treeView.SelectedObject;

			if(node != null) {
				if(GetText("Text","Enter text for node:",node.Text,out string entered)) {
					node.Text = entered;
					treeView.RefreshObject(node);
				}
			}
		}

		private void AddRootNode ()
		{
			if(GetText("Text","Enter text for node:","",out string entered)) {
				treeView.AddObject(new TreeNode(entered));
			}
		}

		private void AddChildNode()
		{
			var node = treeView.SelectedObject;

			if(node != null) {
				if(GetText("Text","Enter text for node:","",out string entered)) {
					node.Children.Add(new TreeNode(entered));
					treeView.RefreshObject(node);
				}
			}
		}

		private bool GetText(string title, string label, string initialText, out string enteredText)
		{
			bool okPressed = false;

			var ok = new Button ("Ok", is_default: true);
			ok.Clicked += () => { okPressed = true; Application.RequestStop (); };
			var cancel = new Button ("Cancel");
			cancel.Clicked += () => { Application.RequestStop (); };
			var d = new Dialog (title, 60, 20, ok, cancel);

			var lbl = new Label() {
				X = 0,
				Y = 1,
				Text = label
			};

			var tf = new TextField()
				{
					Text = initialText,
					X = 0,
					Y = 2,
					Width = Dim.Fill()
				};
			
			d.Add (lbl,tf);
			tf.SetFocus();

			Application.Run (d);

			enteredText = okPressed? tf.Text.ToString() : null;
			return okPressed;
		}

		private void Quit ()
		{
			Application.RequestStop ();
		}
	}
}