Refactor Classic process queue

The queue is now more MVVM-like.

Source/LibationWinForms/ProcessQueue/ProcessBookControl.cs

@@ -22,6 +22,49 @@ namespace LibationWinForms.ProcessQueue
 		public static Color QueuedColor = SystemColors.Control;
 		public static Color SuccessColor = Color.PaleGreen;
 
+		private ProcessBookViewModelBase m_Context;
+		public ProcessBookViewModelBase Context
+		{
+			get => m_Context;
+			set
+			{
+				if (m_Context != value)
+				{
+					OnContextChanging();
+					m_Context = value;
+					OnContextChanged();
+				}
+			}
+		}
+
+		private void OnContextChanging()
+		{
+			if (Context is not null)
+				Context.PropertyChanged -= Context_PropertyChanged;
+		}
+
+		private void OnContextChanged()
+		{
+			Context.PropertyChanged += Context_PropertyChanged;
+			Context_PropertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(null));
+		}
+
+		private void Context_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
+		{
+			SuspendLayout();
+			if (e.PropertyName is null or nameof(Context.Cover))
+				SetCover(Context.Cover as Image);
+			if (e.PropertyName is null or nameof(Context.Title) or nameof(Context.Author) or nameof(Context.Narrator))
+				SetBookInfo($"{Context.Title}\r\nBy {Context.Author}\r\nNarrated by {Context.Narrator}");
+			if (e.PropertyName is null or nameof(Context.Status) or nameof(Context.StatusText))
+				SetStatus(Context.Status, Context.StatusText);
+			if (e.PropertyName is null or nameof(Context.Progress))
+				SetProgress(Context.Progress);
+			if (e.PropertyName is null or nameof(Context.TimeRemaining))
+				SetRemainingTime(Context.TimeRemaining);
+			ResumeLayout();
+		}
+
 		public ProcessBookControl()
 		{
 			InitializeComponent();

Source/LibationWinForms/ProcessQueue/ProcessQueueControl.Designer.cs

@@ -162,7 +162,6 @@
 			this.virtualFlowControl2.Name = "virtualFlowControl2";
 			this.virtualFlowControl2.Size = new System.Drawing.Size(390, 424);
 			this.virtualFlowControl2.TabIndex = 3;
-			this.virtualFlowControl2.VirtualControlCount = 0;
 			// 
 			// panel1
 			// 

Source/LibationWinForms/ProcessQueue/ProcessQueueControl.cs

@@ -1,9 +1,6 @@
 using LibationFileManager;
 using LibationUiBase;
-using LibationUiBase.ProcessQueue;
 using System;
-using System.Collections;
-using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
 using System.Drawing;
@@ -34,12 +31,11 @@ internal partial class ProcessQueueControl : UserControl
 		numericUpDown1.Value = speedLimitMBps > numericUpDown1.Maximum || speedLimitMBps < numericUpDown1.Minimum ? 0 : speedLimitMBps;
 		statusStrip1.Items.Add(PopoutButton);
 
-		virtualFlowControl2.RequestData += VirtualFlowControl1_RequestData;
 		virtualFlowControl2.ButtonClicked += VirtualFlowControl2_ButtonClicked;
 
 		ViewModel.LogWritten += (_, text) => WriteLine(text);
 		ViewModel.PropertyChanged += ProcessQueue_PropertyChanged;
-		ViewModel.BookPropertyChanged += ProcessBook_PropertyChanged;
+		virtualFlowControl2.Items = ViewModel.Items;
 		Load += ProcessQueueControl_Load;
 	}
 
@@ -60,15 +56,13 @@ internal partial class ProcessQueueControl : UserControl
 		ViewModel.Queue.ClearQueue();
 		if (ViewModel.Queue.Current is not null)
 			await ViewModel.Queue.Current.CancelAsync();
-		virtualFlowControl2.VirtualControlCount = ViewModel.Queue.Count;
+		virtualFlowControl2.RefreshDisplay();
-		UpdateAllControls();
 	}
 
 	private void btnClearFinished_Click(object? sender, EventArgs e)
 	{
 		ViewModel.Queue.ClearCompleted();
-		virtualFlowControl2.VirtualControlCount = ViewModel.Queue.Count;
+		virtualFlowControl2.RefreshDisplay();
-		UpdateAllControls();
 
 		if (!ViewModel.Running)
 			runningTimeLbl.Text = string.Empty;
@@ -92,22 +86,13 @@ internal partial class ProcessQueueControl : UserControl
 
 	#region View-Model update event handling
 
-	private void ProcessBook_PropertyChanged(object? sender, PropertyChangedEventArgs e)
-	{
-		if (sender is not ProcessBookViewModel pbvm)
-			return;
-
-		int index = ViewModel.Queue.IndexOf(pbvm);
-		UpdateControl(index, e.PropertyName);
-	}
-
 	private void ProcessQueue_PropertyChanged(object? sender, PropertyChangedEventArgs e)
 	{
 		if (e.PropertyName is null or nameof(ViewModel.QueuedCount))
 		{
 			queueNumberLbl.Text = ViewModel.QueuedCount.ToString();
 			queueNumberLbl.Visible = ViewModel.QueuedCount > 0;
-			virtualFlowControl2.VirtualControlCount = ViewModel.Queue.Count;
+			virtualFlowControl2.RefreshDisplay();
 		}
 		if (e.PropertyName is null or nameof(ViewModel.ErrorCount))
 		{
@@ -134,107 +119,41 @@ internal partial class ProcessQueueControl : UserControl
 		}
 	}
 
-	/// <summary>
-	/// Index of the first <see cref="ProcessBookViewModel"/> visible in the <see cref="VirtualFlowControl"/>
-	/// </summary>
-	private int FirstVisible = 0;
-	/// <summary>
-	/// Number of <see cref="ProcessBookViewModel"/> visible in the <see cref="VirtualFlowControl"/>
-	/// </summary>
-	private int NumVisible = 0;
-	/// <summary>
-	/// Controls displaying the <see cref="ProcessBookViewModel"/> state, starting with <see cref="FirstVisible"/> 
-	/// </summary>
-	private IReadOnlyList<ProcessBookControl>? Panels;
-
-	/// <summary>
-	/// Updates the display of a single <see cref="ProcessBookControl"/> at <paramref name="queueIndex"/> within <see cref="Queue"/>
-	/// </summary>
-	/// <param name="queueIndex">index of the <see cref="ProcessBookViewModel"/> within the <see cref="Queue"/></param>
-	/// <param name="propertyName">The nme of the property that needs updating. If null, all properties are updated.</param>
-	private void UpdateControl(int queueIndex, string? propertyName = null)
-	{
-		try
-		{
-			int i = queueIndex - FirstVisible;
-
-			if (Panels is null || i > NumVisible || i < 0) return;
-
-			var proc = ViewModel.Queue[queueIndex];
-
-			Invoke(() =>
-			{
-				Panels[i].SuspendLayout();
-				if (propertyName is null or nameof(proc.Cover))
-					Panels[i].SetCover(proc.Cover as Image);
-				if (propertyName is null or nameof(proc.Title) or nameof(proc.Author) or nameof(proc.Narrator))
-					Panels[i].SetBookInfo($"{proc.Title}\r\nBy {proc.Author}\r\nNarrated by {proc.Narrator}");
-				if (propertyName is null or nameof(proc.Status) or nameof(proc.StatusText))
-					Panels[i].SetStatus(proc.Status, proc.StatusText);
-				if (propertyName is null or nameof(proc.Progress))
-					Panels[i].SetProgress(proc.Progress);
-				if (propertyName is null or nameof(proc.TimeRemaining))
-					Panels[i].SetRemainingTime(proc.TimeRemaining);
-				Panels[i].ResumeLayout();
-			});
-		}
-		catch (Exception ex)
-		{
-			Serilog.Log.Logger.Error(ex, "Error updating the queued item's display.");
-		}
-	}
-
-	private void UpdateAllControls()
-	{
-		int numToShow = Math.Min(NumVisible, ViewModel.Queue.Count - FirstVisible);
-
-		for (int i = 0; i < numToShow; i++)
-			UpdateControl(FirstVisible + i);
-	}
-
 	/// <summary>
 	/// View notified the model that a botton was clicked
 	/// </summary>
-	/// <param name="queueIndex">index of the <see cref="ProcessBookViewModel"/> within <see cref="Queue"/></param>
+	/// <param name="sender">the <see cref="ProcessBookControl"/> whose button was clicked</param>
-	/// <param name="panelClicked">The clicked control to update</param>
+	/// <param name="buttonName">The name of the button clicked</param>
-	private async void VirtualFlowControl2_ButtonClicked(int queueIndex, string buttonName, ProcessBookControl panelClicked)
+	private async void VirtualFlowControl2_ButtonClicked(object? sender, string buttonName)
 	{
+		if (sender is not ProcessBookControl control || control.Context is not ProcessBookViewModel item)
+			return;
+
 		try
 		{
-			var item = ViewModel.Queue[queueIndex];
+			if (buttonName is nameof(ProcessBookControl.cancelBtn))
-			if (buttonName == nameof(panelClicked.cancelBtn))
 			{
-				if (item is not null)
+				await item.CancelAsync();
+				ViewModel.Queue.RemoveQueued(item);
+				virtualFlowControl2.RefreshDisplay();
+			}
+			else
+			{
+				QueuePosition? position = buttonName switch
 				{
-					await item.CancelAsync();
+					nameof(ProcessBookControl.moveFirstBtn) => QueuePosition.Fisrt,
-					if (ViewModel.Queue.RemoveQueued(item))
+					nameof(ProcessBookControl.moveUpBtn) => QueuePosition.OneUp,
-						virtualFlowControl2.VirtualControlCount = ViewModel.Queue.Count;
+					nameof(ProcessBookControl.moveDownBtn) => QueuePosition.OneDown,
+					nameof(ProcessBookControl.moveLastBtn) => QueuePosition.Last,
+					_ => null
+				};
+
+				if (position is not null)
+				{
+					ViewModel.Queue.MoveQueuePosition(item, position.Value);
+					virtualFlowControl2.RefreshDisplay();
 				}
 			}
-			else if (buttonName == nameof(panelClicked.moveFirstBtn))
-			{
-				ViewModel.Queue.MoveQueuePosition(item, QueuePosition.Fisrt);
-				UpdateAllControls();
-			}
-			else if (buttonName == nameof(panelClicked.moveUpBtn))
-			{
-				ViewModel.Queue.MoveQueuePosition(item, QueuePosition.OneUp);
-				UpdateControl(queueIndex);
-				if (queueIndex > 0)
-					UpdateControl(queueIndex - 1);
-			}
-			else if (buttonName == nameof(panelClicked.moveDownBtn))
-			{
-				ViewModel.Queue.MoveQueuePosition(item, QueuePosition.OneDown);
-				UpdateControl(queueIndex);
-				if (queueIndex + 1 < ViewModel.Queue.Count)
-					UpdateControl(queueIndex + 1);
-			}
-			else if (buttonName == nameof(panelClicked.moveLastBtn))
-			{
-				ViewModel.Queue.MoveQueuePosition(item, QueuePosition.Last);
-				UpdateAllControls();
-			}
 		}
 		catch(Exception ex)
 		{
@@ -242,17 +161,6 @@ internal partial class ProcessQueueControl : UserControl
 		}
 	}
 
-	/// <summary>
-	/// View needs updating
-	/// </summary>
-	private void VirtualFlowControl1_RequestData(int firstIndex, int numVisible, IReadOnlyList<ProcessBookControl> panelsToFill)
-	{
-		FirstVisible = firstIndex;
-		NumVisible = numVisible;
-		Panels = panelsToFill;
-		UpdateAllControls();
-	}
-
 	#endregion
 
 	private void numericUpDown1_ValueChanged(object? sender, EventArgs e)

Source/LibationWinForms/ProcessQueue/ProcessQueueViewModel.cs

@@ -1,11 +1,7 @@
 using DataLayer;
 using LibationUiBase.ProcessQueue;
 using System;
-using System.Collections;
+using System.Collections.Generic;
-using System.Collections.ObjectModel;
-using System.Collections.Specialized;
-using System.ComponentModel;
-using System.Linq;
 
 #nullable enable
 namespace LibationWinForms.ProcessQueue;
@@ -13,62 +9,16 @@ namespace LibationWinForms.ProcessQueue;
 internal class ProcessQueueViewModel : ProcessQueueViewModelBase
 {
 	public event EventHandler<string>? LogWritten;
-	/// <summary>
+	public List<ProcessBookViewModelBase> Items { get; }
-	/// Fires when a ProcessBookViewModelBase in the queue has a property changed
-	/// </summary>
-	public event EventHandler<PropertyChangedEventArgs>? BookPropertyChanged;
-	private ObservableCollection<ProcessBookViewModelBase> Items { get; }
 
-	public ProcessQueueViewModel() : base(CreateEmptyList())
+	public ProcessQueueViewModel() : base(new List<ProcessBookViewModelBase>())
 	{
-		Items = Queue.UnderlyingList as ObservableCollection<ProcessBookViewModelBase>
+		Items = Queue.UnderlyingList as List<ProcessBookViewModelBase>
 			?? throw new ArgumentNullException(nameof(Queue.UnderlyingList));
-		Items.CollectionChanged += Items_CollectionChanged;
 	}
 
-	private void Items_CollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
-	{
-		switch  (e.Action)
-		{
-			case NotifyCollectionChangedAction.Add:
-				subscribe(e.NewItems);
-				break;
-			case NotifyCollectionChangedAction.Remove:
-				unubscribe(e.OldItems);
-				break;
-		}
-
-		void subscribe(IList? items)
-		{
-			foreach (var item in e.NewItems?.OfType<ProcessBookViewModel>() ?? [])
-				item.PropertyChanged += Item_PropertyChanged;
-		}
-
-		void unubscribe(IList? items)
-		{
-			foreach (var item in e.NewItems?.OfType<ProcessBookViewModel>() ?? [])
-				item.PropertyChanged -= Item_PropertyChanged;
-		}
-	}
-
-	private void Item_PropertyChanged(object? sender, PropertyChangedEventArgs e)
-		=> BookPropertyChanged?.Invoke(sender, e);
-
 	public override void WriteLine(string text) => Invoke(() => LogWritten?.Invoke(this, text.Trim()));
 
 	protected override ProcessBookViewModelBase CreateNewProcessBook(LibraryBook libraryBook)
 		=> new ProcessBookViewModel(libraryBook, Logger);
-
-	private static ObservableCollection<ProcessBookViewModelBase> CreateEmptyList()
-		=> new ProcessBookCollection();
-
-	private class ProcessBookCollection : ObservableCollection<ProcessBookViewModelBase>
-	{
-		protected override void ClearItems()
-		{
-			//ObservableCollection doesn't raise Remove for each item on Clear, so we need to do it ourselves.
-			OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, this));
-			base.ClearItems();
-		}
-	}
 }

Source/LibationWinForms/ProcessQueue/VirtualFlowControl.cs

@@ -1,44 +1,42 @@
-using System;
+using LibationUiBase.ProcessQueue;
+using System;
 using System.Collections.Generic;
 using System.Drawing;
 using System.Windows.Forms;
 
 namespace LibationWinForms.ProcessQueue
 {
-
-	internal delegate void RequestDataDelegate(int queueIndex, int numVisible, IReadOnlyList<ProcessBookControl> panelsToFill);
-	internal delegate void ControlButtonClickedDelegate(int queueIndex, string buttonName, ProcessBookControl panelClicked);
 	internal partial class VirtualFlowControl : UserControl
 	{
-		/// <summary>
-		/// Triggered when the <see cref="VirtualFlowControl"/> needs to update the displayed <see cref="ProcessBookControl"/>s
-		/// </summary>
-		public event RequestDataDelegate RequestData;
 		/// <summary>
 		/// Triggered when one of the <see cref="ProcessBookControl"/>'s buttons has been clicked
 		/// </summary>
-		public event ControlButtonClickedDelegate ButtonClicked;
+		public event EventHandler<string> ButtonClicked;
+
+		private List<ProcessBookViewModelBase> m_Items;
+		public List<ProcessBookViewModelBase> Items
+		{
+			get => m_Items;
+			set
+			{
+				m_Items = value;
+				if (m_Items is not null)
+					RefreshDisplay();
+			}
+		}
+
+		public void RefreshDisplay()
+		{
+			AdjustScrollBar();
+			DoVirtualScroll();
+		}
 
 		#region Dynamic Properties
 
 		/// <summary>
 		/// The number of virtual <see cref="ProcessBookControl"/>s in the <see cref="VirtualFlowControl"/>
 		/// </summary>
-		public int VirtualControlCount
+		public int VirtualControlCount => Items?.Count ?? 0;
-		{
-			get => _virtualControlCount;
-			set
-			{
-				if (_virtualControlCount == 0)
-					vScrollBar1.Value = 0;
-
-				_virtualControlCount = value;
-				AdjustScrollBar();
-				DoVirtualScroll();
-			}
-		}
-
-		private int _virtualControlCount;
 
 		int ScrollValue => Math.Max(vScrollBar1.Value, 0);
 		/// <summary>
@@ -100,12 +98,7 @@ namespace LibationWinForms.ProcessQueue
 		{
 			InitializeComponent();
 
-			panel1.Resize += (_, _) =>
+			panel1.Resize += (_, _) => RefreshDisplay();
-			{
-				AdjustScrollBar();
-				DoVirtualScroll();
-			};
-
 
 			var control = InitControl(0);
 			VirtualControlHeight = this.DpiUnscale(control.Height + control.Margin.Top + control.Margin.Bottom);
@@ -151,9 +144,7 @@ namespace LibationWinForms.ProcessQueue
 			while (form is not ProcessBookControl)
 				form = form.Parent;
 
-			int clickedIndex = BookControls.IndexOf((ProcessBookControl)form);
+			ButtonClicked?.Invoke(form, button.Name);
-
-			ButtonClicked?.Invoke(FirstVisibleVirtualIndex + clickedIndex, button.Name, BookControls[clickedIndex]);
 		}
 
 		/// <summary>
@@ -186,7 +177,8 @@ namespace LibationWinForms.ProcessQueue
 
 		/// <summary>
 		/// Calculated the virtual controls that are in view at the currrent scroll position and windows size,
-		/// positions <see cref="panel1"/> to simulate scroll activity, then fires <see cref="RequestData"/> to notify the model to update all visible controls
+		/// positions <see cref="panel1"/> to simulate scroll activity, then fires updates the controls with
+		/// the context corresponding to the virtual scroll position
 		/// </summary>
 		private void DoVirtualScroll()
 		{
@@ -203,10 +195,15 @@ namespace LibationWinForms.ProcessQueue
 			numVisible = Math.Min(numVisible, VirtualControlCount);
 			numVisible = Math.Min(numVisible, VirtualControlCount - firstVisible);
 
-			RequestData?.Invoke(firstVisible, numVisible, BookControls);
+			for (int i = 0; i < numVisible; i++)
+			{
+				BookControls[i].Context = Items[firstVisible + i];
+			}
 
 			for (int i = 0; i < BookControls.Count; i++)
+			{
 				BookControls[i].Visible = i < numVisible;
+			}
 		}
 
 		/// <summary>