port from perforce

intromat/NodeNetworkToolkit/ContextMenu/SearchableContextMenuViewModel.cs

@@ -0,0 +1,126 @@
+using DynamicData;
+using ReactiveUI;
+using System;
+using System.Linq;
+using System.Reactive.Linq;
+using System.Windows.Input;
+
+namespace NodeNetwork.Toolkit.ContextMenu
+{
+    /// <summary>
+    /// A data type containing a command, parameter and display properties.
+    /// </summary>
+    public class LabeledCommand : ReactiveObject
+    {
+        #region Label
+        /// <summary>
+        /// The label that is displayed in the menu
+        /// </summary>
+        public string Label
+        {
+            get => _label;
+            set => this.RaiseAndSetIfChanged(ref _label, value);
+        }
+        private string _label = "";
+        #endregion
+
+        #region Visible
+        /// <summary>
+        /// Should the command be displayed in the menu?
+        /// </summary>
+        public bool Visible
+        {
+            get => _visible;
+            set => this.RaiseAndSetIfChanged(ref _visible, value);
+        }
+        private bool _visible = true;
+        #endregion
+
+        #region Command
+        /// <summary>
+        /// The command to be executed.
+        /// </summary>
+        public ICommand Command
+        {
+            get => _command;
+            set => this.RaiseAndSetIfChanged(ref _command, value);
+        }
+        private ICommand _command = null;
+        #endregion
+
+        #region CommandParameter
+        /// <summary>
+        /// The parameter to be passed to the command on execution.
+        /// </summary>
+        public object CommandParameter
+        {
+            get => _commandParameter;
+            set => this.RaiseAndSetIfChanged(ref _commandParameter, value);
+        }
+        private object _commandParameter = null;
+        #endregion
+    }
+
+    /// <summary>
+    /// A viewmodel for a context menu in which the entries can be filtered by the user based on a searchquery.
+    /// </summary>
+    public class SearchableContextMenuViewModel : ReactiveObject
+    {
+        static SearchableContextMenuViewModel()
+        {
+            NNViewRegistrar.AddRegistration(() => new SearchableContextMenuView(), typeof(IViewFor<SearchableContextMenuViewModel>));
+        }
+
+        /// <summary>
+        /// List of all the available commands in the menu.
+        /// </summary>
+        public ISourceList<LabeledCommand> Commands { get; } = new SourceList<LabeledCommand>();
+
+        /// <summary>
+        /// List of commands that are actually visible in the menu.
+        /// This list is based on Commands and SearchQuery.
+        /// </summary>
+        public IObservableList<LabeledCommand> VisibleCommands { get; }
+
+        #region SearchQuery
+        /// <summary>
+        /// The current search string that is used to filter Nodes into VisibleNodes.
+        /// </summary>
+        public string SearchQuery
+        {
+            get => _searchQuery;
+            set => this.RaiseAndSetIfChanged(ref _searchQuery, value);
+        }
+        private string _searchQuery = "";
+        #endregion
+
+        #region MaxItemsDisplayed
+        /// <summary>
+        /// Only the first MaxItemsDisplayed items from Commands that match the query are displayed.
+        /// </summary>
+        public int MaxItemsDisplayed
+        {
+            get => _maxItemsDisplayed;
+            set => this.RaiseAndSetIfChanged(ref _maxItemsDisplayed, value);
+        }
+        private int _maxItemsDisplayed = int.MaxValue;
+        #endregion
+
+        public SearchableContextMenuViewModel()
+        {
+            var onQueryChanged = 
+                this.WhenAnyValue(vm => vm.SearchQuery, vm => vm.MaxItemsDisplayed)
+                .Throttle(TimeSpan.FromMilliseconds(70), RxApp.MainThreadScheduler)
+                .Publish();
+            onQueryChanged.Connect();
+
+            VisibleCommands = Commands.Connect()
+                .AutoRefreshOnObservable(_ => onQueryChanged)
+                .AutoRefresh(cmd => cmd.Label)
+                .AutoRefresh(cmd => cmd.Visible)
+                .Filter(cmd => cmd.Visible && (cmd.Label ?? "").ToUpper().Contains(SearchQuery?.ToUpper() ?? ""))
+                .Top(MaxItemsDisplayed)
+                .AsObservableList();
+        }
+    }
+}