From 9ad1877a1ecc959b102e845e10a46981b9593f26 Mon Sep 17 00:00:00 2001 From: Edward Miller Date: Fri, 29 Dec 2023 12:31:47 -0600 Subject: [PATCH] Use ObservableRangeCollection from MvvmHelpers to reduce allocations --- Maui.DataGrid/DataGrid.xaml.cs | 17 +- Maui.DataGrid/DataGridRow.cs | 7 + Maui.DataGrid/ObservableRangeCollection.cs | 210 +++++++++++++++++++++ 3 files changed, 225 insertions(+), 9 deletions(-) create mode 100644 Maui.DataGrid/ObservableRangeCollection.cs diff --git a/Maui.DataGrid/DataGrid.xaml.cs b/Maui.DataGrid/DataGrid.xaml.cs index 3c036b3..b1b5441 100644 --- a/Maui.DataGrid/DataGrid.xaml.cs +++ b/Maui.DataGrid/DataGrid.xaml.cs @@ -8,6 +8,7 @@ namespace Maui.DataGrid; using System.Diagnostics; using System.Windows.Input; using Maui.DataGrid.Extensions; +using Microsoft.Maui.Controls; using Microsoft.Maui.Controls.Shapes; using Font = Microsoft.Maui.Font; @@ -36,7 +37,6 @@ public partial class DataGrid private readonly object _reloadLock = new(); private readonly object _sortAndPaginateLock = new(); - private IList? _internalItems; private DataGridColumn? _sortedColumn; #endregion Fields @@ -49,6 +49,7 @@ public partial class DataGrid public DataGrid() { InitializeComponent(); + _collectionView.ItemsSource = InternalItems; _defaultHeaderStyle = (Style)Resources["DefaultHeaderStyle"]; _defaultSortIconStyle = (Style)Resources["DefaultSortIconStyle"]; } @@ -230,11 +231,12 @@ private void SortAndPaginate(SortData? sortData = null) if (PaginationEnabled) { - InternalItems = GetPaginatedItems(sortedItems).ToList(); + var paginatedItems = GetPaginatedItems(sortedItems); + InternalItems.ReplaceRange(paginatedItems); } else { - InternalItems = sortedItems; + InternalItems.ReplaceRange(sortedItems); } } } @@ -542,7 +544,7 @@ private void SortAndPaginate(SortData? sortData = null) throw new InvalidOperationException("DataGrid must have SelectionEnabled=true to set SelectedItem"); } - if (self.InternalItems?.Contains(v) == true) + if (self.InternalItems.Contains(v)) { return v; } @@ -1063,6 +1065,8 @@ private set #pragma warning restore CA2227 // Collection properties should be read only + internal ObservableRangeCollection InternalItems { get; } = []; + #endregion Properties #region UI Methods @@ -1179,11 +1183,6 @@ internal void Reload() UpdatePageSizeList(); InitHeaderView(); - - if (_internalItems is not null) - { - InternalItems = new List(_internalItems); - } } } diff --git a/Maui.DataGrid/DataGridRow.cs b/Maui.DataGrid/DataGridRow.cs index e9b6fc4..f519406 100644 --- a/Maui.DataGrid/DataGridRow.cs +++ b/Maui.DataGrid/DataGridRow.cs @@ -42,11 +42,13 @@ public object RowToEdit if (o is DataGrid oldDataGrid) { oldDataGrid.ItemSelected -= self.DataGrid_ItemSelected; + oldDataGrid.Columns.CollectionChanged += self.OnColumnsChanged; } if (n is DataGrid newDataGrid && newDataGrid.SelectionEnabled) { newDataGrid.ItemSelected += self.DataGrid_ItemSelected; + newDataGrid.Columns.CollectionChanged += self.OnColumnsChanged; } }); @@ -383,6 +385,11 @@ protected override void OnParentSet() } } + private void OnColumnsChanged(object? sender, EventArgs e) + { + CreateView(); + } + private void DataGrid_ItemSelected(object? sender, SelectionChangedEventArgs e) { if (!DataGrid.SelectionEnabled) diff --git a/Maui.DataGrid/ObservableRangeCollection.cs b/Maui.DataGrid/ObservableRangeCollection.cs new file mode 100644 index 0000000..c15464a --- /dev/null +++ b/Maui.DataGrid/ObservableRangeCollection.cs @@ -0,0 +1,210 @@ +/*----------------------------------------------------------------------- + +The MIT License (MIT) +Copyright (c) 2017 James Montemagno +Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: +The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +--------------------------------- +This project also uses the following. +--------------------------------- +MIT License +Copyright (c) 2018 Brandon Minnick (https://github.com/brminnick/AsyncAwaitBestPractices) +Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: +The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +--------------------------------- +Xamarin SDK (https://github.com/xamarin/Xamarin.Forms/) +The MIT License (MIT) +Copyright (c) .NET Foundation Contributors +All rights reserved. +Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: +The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + +-----------------------------------------------------------------------*/ +namespace Maui.DataGrid; + +using System; +using System.Collections.Generic; +using System.Collections.ObjectModel; +using System.Collections.Specialized; +using System.ComponentModel; + +/// +/// Represents a dynamic data collection that provides notifications when items get added, removed, or when the whole list is refreshed. +/// +/// The object type of elements in the collection. +internal sealed class ObservableRangeCollection : ObservableCollection +{ + /// + /// Initializes a new instance of the class. + /// + public ObservableRangeCollection() + { + } + + /// + /// Initializes a new instance of the class that contains elements copied from the specified collection. + /// + /// collection: The collection from which the elements are copied. + /// The collection parameter cannot be null. + public ObservableRangeCollection(IEnumerable collection) + : base(collection) + { + } + + /// + /// Adds the elements of the specified collection to the end of the ObservableCollection(Of T). + /// + /// The collection to add. + /// The notification mode. + /// An exception when an invalid notification mode is set. + public void AddRange(IEnumerable collection, NotifyCollectionChangedAction notificationMode = NotifyCollectionChangedAction.Add) + { + if (notificationMode is not NotifyCollectionChangedAction.Add and not NotifyCollectionChangedAction.Reset) + { + throw new ArgumentException("Mode must be either Add or Reset for AddRange.", nameof(notificationMode)); + } + + ArgumentNullException.ThrowIfNull(collection); + + CheckReentrancy(); + + var startIndex = Count; + + var itemsAdded = AddArrangeCore(collection); + + if (!itemsAdded) + { + return; + } + + if (notificationMode == NotifyCollectionChangedAction.Reset) + { + RaiseChangeNotificationEvents(action: NotifyCollectionChangedAction.Reset); + + return; + } + + var changedItems = collection is List list ? list : new List(collection); + + RaiseChangeNotificationEvents( + action: NotifyCollectionChangedAction.Add, + changedItems: changedItems, + startingIndex: startIndex); + } + + /// + /// Removes the first occurrence of each item in the specified collection from ObservableCollection(Of T). NOTE: with notificationMode = Remove, removed items starting index is not set because items are not guaranteed to be consecutive. + /// + /// The collection to remove. + /// The notification mode. + /// An exception when an invalid notification mode is set. + public void RemoveRange(IEnumerable collection, NotifyCollectionChangedAction notificationMode = NotifyCollectionChangedAction.Reset) + { + if (notificationMode is not NotifyCollectionChangedAction.Remove and not NotifyCollectionChangedAction.Reset) + { + throw new ArgumentException("Mode must be either Remove or Reset for RemoveRange.", nameof(notificationMode)); + } + + ArgumentNullException.ThrowIfNull(collection); + + CheckReentrancy(); + + if (notificationMode == NotifyCollectionChangedAction.Reset) + { + var raiseEvents = false; + foreach (var item in collection) + { + _ = Items.Remove(item); + raiseEvents = true; + } + + if (raiseEvents) + { + RaiseChangeNotificationEvents(action: NotifyCollectionChangedAction.Reset); + } + + return; + } + + var changedItems = new List(collection); + for (var i = 0; i < changedItems.Count; i++) + { + if (!Items.Remove(changedItems[i])) + { + changedItems.RemoveAt(i); // Can't use a foreach because changedItems is intended to be (carefully) modified + i--; + } + } + + if (changedItems.Count == 0) + { + return; + } + + RaiseChangeNotificationEvents( + action: NotifyCollectionChangedAction.Remove, + changedItems: changedItems); + } + + /// + /// Clears the current collection and replaces it with the specified item. + /// + /// The item to replace the collection with. + public void Replace(T item) => ReplaceRange(new T[] { item }); + + /// + /// Clears the current collection and replaces it with the specified collection. + /// + /// The collection to replace with. + public void ReplaceRange(IEnumerable collection) + { + ArgumentNullException.ThrowIfNull(collection); + + CheckReentrancy(); + + var previouslyEmpty = Items.Count == 0; + + Items.Clear(); + + _ = AddArrangeCore(collection); + + var currentlyEmpty = Items.Count == 0; + + if (previouslyEmpty && currentlyEmpty) + { + return; + } + + RaiseChangeNotificationEvents(action: NotifyCollectionChangedAction.Reset); + } + + private bool AddArrangeCore(IEnumerable collection) + { + var itemAdded = false; + foreach (var item in collection) + { + Items.Add(item); + itemAdded = true; + } + + return itemAdded; + } + + private void RaiseChangeNotificationEvents(NotifyCollectionChangedAction action, List? changedItems = null, int startingIndex = -1) + { + OnPropertyChanged(new PropertyChangedEventArgs(nameof(Count))); + OnPropertyChanged(new PropertyChangedEventArgs("Item[]")); + + if (changedItems is null) + { + OnCollectionChanged(new NotifyCollectionChangedEventArgs(action)); + } + else + { + OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, changedItems: changedItems, startingIndex: startingIndex)); + } + } +}