Added a sortable variant of the BindingList class (useful in getting DataGridViews to be not quite so silly)

git-svn-id: file:///srv/devel/repo-conversion/nusu@342 d2e56fa2-650e-0410-a79f-9358c0239efd

Nuclex.Support (net-4.0).csproj

@@ -194,6 +194,10 @@
     <Compile Include="Source\Collections\ReverseComparer.Test.cs">
       <DependentUpon>ReverseComparer.cs</DependentUpon>
     </Compile>
+    <Compile Include="Source\Collections\SortableBindingList.cs" />
+    <Compile Include="Source\Collections\SortableBindingList.Test.cs">
+      <DependentUpon>SortableBindingList.cs</DependentUpon>
+    </Compile>
     <Compile Include="Source\Collections\TransformingReadOnlyCollection.cs" />
     <Compile Include="Source\Collections\TransformingReadOnlyCollection.Interfaces.cs">
       <DependentUpon>TransformingReadOnlyCollection.cs</DependentUpon>

Source/Collections/IListExtensions.Test.cs

@@ -32,6 +32,20 @@ namespace Nuclex.Support.Collections {
   [TestFixture]
   internal class IListExtensionsTest {
 
+    /// <summary>Tests whether the insertion sort algorithm sorts a list correctly</summary>
+    [Test]
+    public void InsertionSortCanSortWholeList() {
+      var testList = new List<int>(capacity: 5) { 1, 5, 2, 4, 3 };
+      var testListAsIList = (IList<int>)testList;
+
+      testListAsIList.InsertionSort();
+
+      CollectionAssert.AreEqual(
+        new List<int>(capacity: 5) { 1, 2, 3, 4, 5 },
+        testList
+      );
+    }
+
     /// <summary>Tests whether the insertion sort algorithm works on big lists</summary>
     [Test]
     public void InsertionSortCanSortBigList() {
@@ -53,21 +67,7 @@ namespace Nuclex.Support.Collections {
       }
     }
 
-    /// <summary>Tests whether the insertion sort algorithm can be applied to 'Text' property works as expected</summary>
-    [Test]
-    public void InsertionSortCanSortWholeList() {
-      var testList = new List<int>(capacity: 5) { 1, 5, 2, 4, 3 };
-      var testListAsIList = (IList<int>)testList;
-      
-      testListAsIList.InsertionSort();
-
-      CollectionAssert.AreEqual(
-        new List<int>(capacity: 5) { 1, 2, 3, 4, 5 },
-        testList
-      );
-    }
-
-    /// <summary>Tests whether the 'Text' property works as expected</summary>
+    /// <summary>Tests whether the insertion sort algorithm respects custom boundaries</summary>
     [Test]
     public void InsertionSortCanSortListSegment() {
       var testList = new List<int>(capacity: 7) { 9, 1, 5, 2, 4, 3, 0 };
@@ -81,6 +81,20 @@ namespace Nuclex.Support.Collections {
       );
     }
 
+    /// <summary>Tests whether the quicksort algorithm sorts a list correctly</summary>
+    [Test]
+    public void QuickSortCanSortWholeList() {
+      var testList = new List<int>(capacity: 5) { 1, 5, 2, 4, 3 };
+      var testListAsIList = (IList<int>)testList;
+
+      testListAsIList.QuickSort();
+
+      CollectionAssert.AreEqual(
+        new List<int>(capacity: 5) { 1, 2, 3, 4, 5 },
+        testList
+      );
+    }
+
     /// <summary>Tests whether the quicksort algorithm works on big lists</summary>
     [Test]
     public void QuickSortCanSortBigList() {
@@ -102,21 +116,20 @@ namespace Nuclex.Support.Collections {
       }
     }
 
-    /// <summary>Tests whether the insertion sort algorithm can be applied to 'Text' property works as expected</summary>
+    /// <summary>Tests whether the quicksort algorithm respects custom boundaries</summary>
     [Test]
-    public void QuickSortCanSortWholeList() {
-      var testList = new List<int>(capacity: 5) { 1, 5, 2, 4, 3 };
+    public void QuickSortCanSortListSegment() {
+      var testList = new List<int>(capacity: 7) { 9, 1, 5, 2, 4, 3, 0 };
       var testListAsIList = (IList<int>)testList;
 
-      testListAsIList.QuickSort();
+      testListAsIList.QuickSort(1, 5, Comparer<int>.Default);
 
       CollectionAssert.AreEqual(
-        new List<int>(capacity: 5) { 1, 2, 3, 4, 5 },
+        new List<int>(capacity: 7) { 9, 1, 2, 3, 4, 5, 0 },
         testList
       );
     }
 
-
   }
 
 } // namespace Nuclex.Support.Collections

Source/Collections/IListExtensions.cs

@@ -19,7 +19,6 @@ License along with this library
 #endregion
 
 using System;
-using System.Collections;
 using System.Collections.Generic;
 
 namespace Nuclex.Support.Collections {

Source/Collections/SortableBindingList.Test.cs

@@ -0,0 +1,120 @@
+#region CPL License
+/*
+Nuclex Framework
+Copyright (C) 2002-2017 Nuclex Development Labs
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the IBM Common Public License as
+published by the IBM Corporation; either version 1.0 of the
+License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+IBM Common Public License for more details.
+
+You should have received a copy of the IBM Common Public
+License along with this library
+*/
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Reflection;
+
+#if UNITTEST
+
+using NUnit.Framework;
+
+namespace Nuclex.Support.Collections {
+
+  /// <summary>Unit Test for the SortableBindingList class</summary>
+  [TestFixture]
+  internal class SortableBindingListTest {
+
+    #region class TestRecord
+
+    /// <summary>Dummy record used to test the sortable binding list</summary>
+    private class TestRecord {
+
+      /// <summary>A property of type integer</summary>
+      public int IntegerValue { get; set; }
+
+      /// <summary>A property of type string</summary>
+      public string StringValue { get; set; }
+
+      /// <summary>A property of type float</summary>
+      public float FloatValue { get; set; }
+
+    }
+
+    #endregion // class TestRecord
+
+    /// <summary>Verifies that the sortable binding list is default constructible</summary>
+    [Test]
+    public void HasDefaultConstructor() {
+      Assert.DoesNotThrow(
+        delegate () { new SortableBindingList<TestRecord>(); }
+      );
+    }
+
+    /// <summary>
+    ///   Tests whether the sortable binding list can copy an existing list
+    ///   when being constructed
+    /// </summary>
+    [Test]
+    public void HasEnumerableConstructor() {
+      var items = new List<TestRecord>() {
+        new TestRecord() { IntegerValue = 123 },
+        new TestRecord() { IntegerValue = 456 }
+      };
+
+      var testList = new SortableBindingList<TestRecord>(items);
+
+      Assert.AreEqual(2, testList.Count);
+      Assert.AreSame(items[0], testList[0]);
+      Assert.AreSame(items[1], testList[1]);
+    }
+
+    /// <summary>Verifies that the sortable binding list supports sorting</summary>
+    [Test]
+    public void SupportsSorting() {
+      var testList = new SortableBindingList<TestRecord>();
+      IBindingList testListAsBindingList = testList;
+
+      Assert.IsTrue(testListAsBindingList.SupportsSorting);
+    }
+
+    /// <summary>
+    ///   Tests whether the sortable binding list can sort its elements by different properties
+    /// </summary>
+    [Test]
+    public void CanSortItems() {
+      var items = new List<TestRecord>() {
+        new TestRecord() { IntegerValue = 456 },
+        new TestRecord() { IntegerValue = 789 },
+        new TestRecord() { IntegerValue = 123 }
+      };
+
+      var testList = new SortableBindingList<TestRecord>(items);
+      IBindingList testListAsBindingList = testList;
+
+      PropertyDescriptor integerValuePropertyDescriptor = (
+        TypeDescriptor.GetProperties(typeof(TestRecord))[nameof(TestRecord.IntegerValue)]
+      );
+      testListAsBindingList.ApplySort(
+        integerValuePropertyDescriptor, ListSortDirection.Ascending
+      );
+
+      Assert.AreEqual(3, testList.Count);
+      Assert.AreEqual(123, testList[0].IntegerValue);
+      Assert.AreEqual(456, testList[1].IntegerValue);
+      Assert.AreEqual(789, testList[2].IntegerValue);
+    }
+
+  }
+
+} // namespace Nuclex.Support.Collections
+
+#endif // UNITTEST

Source/Collections/SortableBindingList.cs

@@ -0,0 +1,223 @@
+#region CPL License
+/*
+Nuclex Framework
+Copyright (C) 2002-2017 Nuclex Development Labs
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the IBM Common Public License as
+published by the IBM Corporation; either version 1.0 of the
+License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+IBM Common Public License for more details.
+
+You should have received a copy of the IBM Common Public
+License along with this library
+*/
+#endregion
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Reflection;
+
+namespace Nuclex.Support.Collections {
+
+  /// <summary>Variant of BindingList that supports sorting</summary>
+  /// <typeparam name="TElement">Type of items the binding list will contain</typeparam>
+  internal class SortableBindingList<TElement> : BindingList<TElement> {
+
+    #region class PropertyComparer
+
+    /// <summary>Compares two elements based on a single preselected property</summary>
+    private class PropertyComparer : IComparer<TElement> {
+
+      /// <summary>Initializes a new property comparer for the specified property</summary>
+      /// <param name="property">Property based on which elements should be compared</param>
+      /// <param name="direction">Direction in which elements should be sorted</param>
+      public PropertyComparer(PropertyDescriptor property, ListSortDirection direction) {
+        this.propertyDescriptor = property;
+
+        Type comparerForPropertyType = typeof(Comparer<>).MakeGenericType(property.PropertyType);
+        this.comparer = (IComparer)comparerForPropertyType.InvokeMember(
+          "Default",
+          BindingFlags.Static | BindingFlags.GetProperty | BindingFlags.Public,
+          null, // binder
+          null, // target (none since method is static)
+          null // argument array
+        );
+
+        SetListSortDirection(direction);
+      }
+
+      /// <summary>Compares two elements based on the comparer's chosen property</summary>
+      /// <param name="first">First element for the comparison</param>
+      /// <param name="second">Second element for the comparison</param>
+      /// <returns>The relationship of the two elements to each other</returns>
+      public int Compare(TElement first, TElement second) {
+        return this.comparer.Compare(
+          this.propertyDescriptor.GetValue(first),
+          this.propertyDescriptor.GetValue(second)
+        ) * this.reverse;
+      }
+
+      /// <summary>Selects the property based on which elements should be compared</summary>
+      /// <param name="descriptor">Descriptor for the property to use for comparison</param>
+      private void SetPropertyDescriptor(PropertyDescriptor descriptor) {
+        this.propertyDescriptor = descriptor;
+      }
+
+      /// <summary>Changes the sort direction</summary>
+      /// <param name="direction">New sort direction</param>
+      private void SetListSortDirection(ListSortDirection direction) {
+        this.reverse = direction == ListSortDirection.Ascending ? 1 : -1;
+      }
+
+      /// <summary>Updtes the sorted proeprty and the sort direction</summary>
+      /// <param name="descriptor">Property based on which elements will be sorted</param>
+      /// <param name="direction">Direction in which elements will be sorted</param>
+      public void SetPropertyAndDirection(
+        PropertyDescriptor descriptor, ListSortDirection direction
+      ) {
+        SetPropertyDescriptor(descriptor);
+        SetListSortDirection(direction);
+      }
+
+      /// <summary>The default comparer for the type of the chosen property</summary>
+      private readonly IComparer comparer;
+      /// <summary>Descriptor for the chosen property</summary>
+      private PropertyDescriptor propertyDescriptor;
+      /// <summary>
+      ///   Either positive or negative 1 to change the sign of the comparison result
+      /// </summary>
+      private int reverse;
+
+    }
+
+    #endregion // class PropertyComparer
+
+    /// <summary>Initializes a new BindingList with support for sorting</summary>
+    public SortableBindingList() : base(new List<TElement>()) {
+      this.comparers = new Dictionary<Type, PropertyComparer>();
+    }
+
+    /// <summary>
+    ///   Initializes a sortable BindingList, copying the contents of an existing list
+    /// </summary>
+    /// <param name="enumeration">Existing list whose contents will be shallo-wcopied</param>
+    public SortableBindingList(IEnumerable<TElement> enumeration) :
+      base(new List<TElement>(enumeration)) {
+      this.comparers = new Dictionary<Type, PropertyComparer>();
+    }
+
+    /// <summary>
+    ///   Used by BindingList implementation to check whether sorting is supported
+    /// </summary>
+    protected override bool SupportsSortingCore {
+      get { return true; }
+    }
+
+    /// <summary>
+    ///   Used by BindingList implementation to check whether the list is currently sorted
+    /// </summary>
+    protected override bool IsSortedCore {
+      get { return this.isSorted; }
+    }
+
+    /// <summary>
+    ///   Used by BindingList implementation to track the property the list is sorted by
+    /// </summary>
+    protected override PropertyDescriptor SortPropertyCore {
+      get { return this.propertyDescriptor; }
+    }
+
+    /// <summary>
+    ///   Used by BindingList implementation to track the direction in which the list is sortd
+    /// </summary>
+    protected override ListSortDirection SortDirectionCore {
+      get { return this.listSortDirection; }
+    }
+
+    /// <summary>
+    ///   Used by BindingList implementation to check whether the list supports searching
+    /// </summary>
+    protected override bool SupportsSearchingCore {
+      get { return true; }
+    }
+
+    /// <summary>
+    ///   Used by BindingList implementation to sort the elements in the backing collection
+    /// </summary>
+    protected override void ApplySortCore(PropertyDescriptor property, ListSortDirection direction) {
+
+      // Obtain a property comparer that sorts on the attributes the SortableBindingList
+      // has been configured for its sort order
+      PropertyComparer comparer;
+      {
+        Type propertyType = property.PropertyType;
+
+        if(!this.comparers.TryGetValue(propertyType, out comparer)) {
+          comparer = new PropertyComparer(property, direction);
+          this.comparers.Add(propertyType, comparer);
+        }
+
+        // Direction may need to be updated
+        comparer.SetPropertyAndDirection(property, direction);
+      }
+
+      // Check to see if our base class is using a standard List<> in which case
+      // we'll sneakily use the downcast to call the List<>.Sort() method, otherwise
+      // there's still our own quicksort implementation for IList<>.
+      List<TElement> itemsAsList = this.Items as List<TElement>;
+      if(itemsAsList != null) {
+        itemsAsList.Sort(comparer);
+      } else {
+        this.Items.QuickSort(0, this.Items.Count, comparer); // from IListExtensions
+      }
+
+      this.propertyDescriptor = property;
+      this.listSortDirection = direction;
+      this.isSorted = true;
+
+      OnListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1));
+    }
+
+    /// <summary>Used by BindingList implementation to undo any sorting that took place</summary>
+    protected override void RemoveSortCore() {
+      this.isSorted = false;
+      this.propertyDescriptor = base.SortPropertyCore;
+      this.listSortDirection = base.SortDirectionCore;
+
+      OnListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1));
+    }
+
+    /// <summary>
+    ///   Used by BindingList implementation to run a search on any of the element's properties
+    /// </summary>
+    protected override int FindCore(PropertyDescriptor property, object key) {
+      int count = this.Count;
+      for(int index = 0; index < count; ++index) {
+        TElement element = this[index];
+        if(property.GetValue(element).Equals(key)) {
+          return index;
+        }
+      }
+
+      return -1;
+    }
+
+    /// <summary>Cached property comparers, created for each element property as needed</summary>
+    private readonly Dictionary<Type, PropertyComparer> comparers;
+    /// <summary>Whether the binding list is currently sorted</summary>
+    private bool isSorted;
+    /// <summary>Direction in which the binding list is currently sorted</summary>
+    private ListSortDirection listSortDirection;
+    /// <summary>Descriptor for the property by which the binding list is currently sorted</summary>
+    private PropertyDescriptor propertyDescriptor;
+
+  }
+
+} // namespace Nuclex.Support.Collections