Move filter query and RowComparer into UI base

Source/LibationAvalonia/ViewModels/ProductsDisplayViewModel.cs

@@ -23,7 +23,7 @@ namespace LibationAvalonia.ViewModels
 		/// <summary>Backing list of all grid entries</summary>
 		private readonly AvaloniaList<IGridEntry> SOURCE = new();
 		/// <summary>Grid entries included in the filter set. If null, all grid entries are shown</summary>
-		private List<IGridEntry> FilteredInGridEntries;
+		private HashSet<IGridEntry> FilteredInGridEntries;
 		public string FilterString { get; private set; }
 		public DataGridCollectionView GridEntries { get; private set; }
 
@@ -117,7 +117,7 @@ namespace LibationAvalonia.ViewModels
 			}
 
 			//Create the filtered-in list before adding entries to avoid a refresh
-			FilteredInGridEntries = QueryResults(geList.Union(geList.OfType<ISeriesEntry>().SelectMany(s => s.Children)), FilterString);
+			FilteredInGridEntries = geList.Union(geList.OfType<ISeriesEntry>().SelectMany(s => s.Children)).FilterEntries(FilterString);
 			SOURCE.AddRange(geList.OrderByDescending(e => e.DateAdded));
 
 			//Add all children beneath their parent
@@ -301,7 +301,7 @@ namespace LibationAvalonia.ViewModels
 			if (SOURCE.Count == 0)
 				return;
 
-			FilteredInGridEntries = QueryResults(SOURCE, searchString);
+			FilteredInGridEntries = SOURCE.FilterEntries(searchString);
 
 			await refreshGrid();
 		}
@@ -318,23 +318,9 @@ namespace LibationAvalonia.ViewModels
 			return FilteredInGridEntries.Contains(item);
 		}
 
-		private static List<IGridEntry> QueryResults(IEnumerable<IGridEntry> entries, string searchString)
-		{
-			if (string.IsNullOrEmpty(searchString)) return null;
-
-			var searchResultSet = SearchEngineCommands.Search(searchString);
-
-			var booksFilteredIn = entries.BookEntries().Join(searchResultSet.Docs, lbe => lbe.AudibleProductId, d => d.ProductId, (lbe, d) => (IGridEntry)lbe);
-
-			//Find all series containing children that match the search criteria
-			var seriesFilteredIn = entries.SeriesEntries().Where(s => s.Children.Join(searchResultSet.Docs, lbe => lbe.AudibleProductId, d => d.ProductId, (lbe, d) => lbe).Any());
-
-			return booksFilteredIn.Concat(seriesFilteredIn).ToList();
-		}
-
 		private async void SearchEngineCommands_SearchEngineUpdated(object sender, EventArgs e)
 		{
-			var filterResults = QueryResults(SOURCE, FilterString);
+			var filterResults = SOURCE.FilterEntries(FilterString);
 
 			if (filterResults is not null && FilteredInGridEntries.Intersect(filterResults).Count() != FilteredInGridEntries.Count)
 			{

Source/LibationAvalonia/ViewModels/RowComparer.cs

@@ -1,25 +1,17 @@
 using Avalonia.Controls;
 using LibationUiBase.GridView;
-using System.Collections;
-using System.Collections.Generic;
 using System.ComponentModel;
 using System.Reflection;
 
 namespace LibationAvalonia.ViewModels
 {
-	/// <summary>
+	internal class RowComparer : RowComparerBase
-	/// This compare class ensures that all top-level grid entries (standalone books or series parents)
-	/// are sorted by PropertyName while all episodes remain immediately beneath their parents and remain
-	/// sorted by series index, ascending. Stable sorting is achieved by comparing the GridEntry.ListIndex
-	/// properties when 2 items compare equal.
-	/// </summary>
-	internal class RowComparer : IComparer, IComparer<IGridEntry>, IComparer<object>
 	{
 		private static readonly PropertyInfo HeaderCellPi = typeof(DataGridColumn).GetProperty("HeaderCell", BindingFlags.NonPublic | BindingFlags.Instance);
 		private static readonly PropertyInfo CurrentSortingStatePi = typeof(DataGridColumnHeader).GetProperty("CurrentSortingState", BindingFlags.NonPublic | BindingFlags.Instance);
 
-		public DataGridColumn Column { get; init; }
+		private DataGridColumn Column { get; init; }
-		public string PropertyName { get; private set; }
+		public override string PropertyName { get; set; }
 
 		public RowComparer(DataGridColumn column)
 		{
@@ -27,72 +19,8 @@ namespace LibationAvalonia.ViewModels
 			PropertyName = Column.SortMemberPath;
 		}
 
-		public int Compare(object x, object y)
-		{
-			if (x is null && y is not null) return -1;
-			if (x is not null && y is null) return 1;
-			if (x is null && y is null) return 0;
-
-			var geA = (IGridEntry)x;
-			var geB = (IGridEntry)y;
-
-			var sortDirection = GetSortOrder();
-
-			ISeriesEntry parentA = null;
-			ISeriesEntry parentB = null;
-
-			if (geA is ILibraryBookEntry lbA && lbA.Parent is ISeriesEntry seA)
-				parentA = seA;
-			if (geB is ILibraryBookEntry lbB && lbB.Parent is ISeriesEntry seB)
-				parentB = seB;
-
-			//both a and b are top-level grid entries
-			if (parentA is null && parentB is null)
-				return InternalCompare(geA, geB);
-
-			//a is top-level, b is a child
-			if (parentA is null && parentB is not null)
-			{
-				// b is a child of a, parent is always first
-				if (parentB == geA)
-					return sortDirection is ListSortDirection.Ascending ? -1 : 1;
-				else
-					return InternalCompare(geA, parentB);
-			}
-
-			//a is a child, b is a top-level
-			if (parentA is not null && parentB is null)
-			{
-				// a is a child of b, parent is always first
-				if (parentA == geB)
-					return sortDirection is ListSortDirection.Ascending ? 1 : -1;
-				else
-					return InternalCompare(parentA, geB);
-			}
-
-			//both are children of the same series
-			if (parentA == parentB)
-				return InternalCompare(geA, geB);
-
-			//a and b are children of different series.
-			return InternalCompare(parentA, parentB);
-		}
-
 		//Avalonia doesn't expose the column's CurrentSortingState, so we must get it through reflection
-		private ListSortDirection? GetSortOrder()
+		protected override ListSortDirection? GetSortOrder()
 			=> CurrentSortingStatePi.GetValue(HeaderCellPi.GetValue(Column)) as ListSortDirection?;
-
-		private int InternalCompare(IGridEntry x, IGridEntry y)
-		{
-			var val1 = x.GetMemberValue(PropertyName);
-			var val2 = y.GetMemberValue(PropertyName);
-
-			return x.GetMemberComparer(val1.GetType()).Compare(val1, val2); ;
-		}
-
-		public int Compare(IGridEntry x, IGridEntry y)
-		{
-			return Compare((object)x, y);
-		}
 	}
 }

Source/LibationUiBase/GridView/QueryExtensions.cs

@@ -1,4 +1,5 @@
-using DataLayer;
+using ApplicationServices;
+using DataLayer;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -39,6 +40,20 @@ namespace LibationUiBase.GridView
 				return null;
 			}
 		}
+
+		public static HashSet<IGridEntry>? FilterEntries(this IEnumerable<IGridEntry> entries, string searchString)
+		{
+			if (string.IsNullOrEmpty(searchString)) return null;
+
+			var searchResultSet = SearchEngineCommands.Search(searchString);
+
+			var booksFilteredIn = entries.BookEntries().Join(searchResultSet.Docs, lbe => lbe.AudibleProductId, d => d.ProductId, (lbe, d) => (IGridEntry)lbe);
+
+			//Find all series containing children that match the search criteria
+			var seriesFilteredIn = entries.SeriesEntries().Where(s => s.Children.Join(searchResultSet.Docs, lbe => lbe.AudibleProductId, d => d.ProductId, (lbe, d) => lbe).Any());
+
+			return booksFilteredIn.Concat(seriesFilteredIn).ToHashSet();
+		}
 	}
 #nullable disable
 }

Source/LibationUiBase/GridView/RowComparerBase.cs

@@ -0,0 +1,82 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel;
+
+namespace LibationUiBase.GridView
+{
+	/// <summary>
+	/// This compare class ensures that all top-level grid entries (standalone books or series parents)
+	/// are sorted by PropertyName while all episodes remain immediately beneath their parents and remain
+	/// sorted by series index, ascending.
+	/// </summary>
+	public abstract class RowComparerBase : IComparer, IComparer<IGridEntry>, IComparer<object>
+	{
+		public abstract string PropertyName { get; set; }
+
+		public int Compare(object x, object y)
+		{
+			if (x is null && y is not null) return -1;
+			if (x is not null && y is null) return 1;
+			if (x is null && y is null) return 0;
+
+			var geA = (IGridEntry)x;
+			var geB = (IGridEntry)y;
+
+			var sortDirection = GetSortOrder();
+
+			ISeriesEntry parentA = null;
+			ISeriesEntry parentB = null;
+
+			if (geA is ILibraryBookEntry lbA && lbA.Parent is ISeriesEntry seA)
+				parentA = seA;
+			if (geB is ILibraryBookEntry lbB && lbB.Parent is ISeriesEntry seB)
+				parentB = seB;
+
+			//both a and b are top-level grid entries
+			if (parentA is null && parentB is null)
+				return InternalCompare(geA, geB);
+
+			//a is top-level, b is a child
+			if (parentA is null && parentB is not null)
+			{
+				// b is a child of a, parent is always first
+				if (parentB == geA)
+					return sortDirection is ListSortDirection.Ascending ? -1 : 1;
+				else
+					return InternalCompare(geA, parentB);
+			}
+
+			//a is a child, b is a top-level
+			if (parentA is not null && parentB is null)
+			{
+				// a is a child of b, parent is always first
+				if (parentA == geB)
+					return sortDirection is ListSortDirection.Ascending ? 1 : -1;
+				else
+					return InternalCompare(parentA, geB);
+			}
+
+			//both are children of the same series
+			if (parentA == parentB)
+				return InternalCompare(geA, geB);
+
+			//a and b are children of different series.
+			return InternalCompare(parentA, parentB);
+		}
+
+		protected abstract ListSortDirection? GetSortOrder();
+
+		private int InternalCompare(IGridEntry x, IGridEntry y)
+		{
+			var val1 = x.GetMemberValue(PropertyName);
+			var val2 = y.GetMemberValue(PropertyName);
+
+			return x.GetMemberComparer(val1.GetType()).Compare(val1, val2); ;
+		}
+
+		public int Compare(IGridEntry x, IGridEntry y)
+		{
+			return Compare((object)x, y);
+		}
+	}
+}