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add add/remove extension methods

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Vincent 2020-04-21 00:07:06 +02:00
parent 8ca869469e
commit 47f1bcc5ea
1 changed files with 190 additions and 0 deletions

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Microsoft.Toolkit/Collections/ObservableGroupedCollectionExtensions.cs Normal file
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System.Collections.Generic;
using System.Linq;
namespace Microsoft.Toolkit.Collections
{
/// <summary>
/// The extensions methods to simplify the usage of <see cref="ObservableGroupedCollection{TKey, TValue}"/>.
/// </summary>
public static class ObservableGroupedCollectionExtensions
{
/// <summary>
/// Adds a key-value <see cref="ObservableGroup{TKey, TValue}"/> item into a target <see cref="ObservableGroupedCollection{TKey, TValue}"/>.
/// </summary>
/// <typeparam name="TKey">The type of the group key.</typeparam>
/// <typeparam name="TValue">The type of the items in the collection.</typeparam>
/// <param name="source">The source <see cref="ObservableGroupedCollection{TKey, TValue}"/> instance.</param>
/// <param name="key">The key to add.</param>
/// <param name="value">The value to add.</param>
/// <returns>The added <see cref="ObservableGroup{TKey, TValue}"/>.</returns>
public static ObservableGroup<TKey, TValue> AddGroup<TKey, TValue>(
this ObservableGroupedCollection<TKey, TValue> source,
TKey key,
TValue value)
=> AddGroup(source, key, new[] { value });
/// <summary>
/// Adds a key-collection <see cref="ObservableGroup{TKey, TValue}"/> item into a target <see cref="ObservableGroupedCollection{TKey, TValue}"/>.
/// </summary>
/// <typeparam name="TKey">The type of the group key.</typeparam>
/// <typeparam name="TValue">The type of the items in the collection.</typeparam>
/// <param name="source">The source <see cref="ObservableGroupedCollection{TKey, TValue}"/> instance.</param>
/// <param name="key">The key to add.</param>
/// <param name="collection">The collection to add.</param>
/// <returns>The added <see cref="ObservableGroup{TKey, TValue}"/>.</returns>
public static ObservableGroup<TKey, TValue> AddGroup<TKey, TValue>(
this ObservableGroupedCollection<TKey, TValue> source,
TKey key,
params TValue[] collection)
=> source.AddGroup(key, (IEnumerable<TValue>)collection);
/// <summary>
/// Adds a key-collection <see cref="ObservableGroup{TKey, TValue}"/> item into a target <see cref="ObservableGroupedCollection{TKey, TValue}"/>.
/// </summary>
/// <typeparam name="TKey">The type of the group key.</typeparam>
/// <typeparam name="TValue">The type of the items in the collection.</typeparam>
/// <param name="source">The source <see cref="ObservableGroupedCollection{TKey, TValue}"/> instance.</param>
/// <param name="key">The key to add.</param>
/// <param name="collection">The collection to add.</param>
/// <returns>The added <see cref="ObservableGroup{TKey, TValue}"/>.</returns>
public static ObservableGroup<TKey, TValue> AddGroup<TKey, TValue>(
this ObservableGroupedCollection<TKey, TValue> source,
TKey key,
IEnumerable<TValue> collection)
{
var group = new ObservableGroup<TKey, TValue>(key, collection);
source.Add(group);
return group;
}
/// <summary>
/// Add <paramref name="item"/> into the group with <paramref name="key"/> key.
/// If the group does not exist, it will be added.
/// If several groups exist with the same key, <paramref name="item"/> will be added to the first group.
/// </summary>
/// <typeparam name="TKey">The type of the group key.</typeparam>
/// <typeparam name="TValue">The type of the items in the collection.</typeparam>
/// <param name="source">The source <see cref="ObservableGroupedCollection{TKey, TValue}"/> instance.</param>
/// <param name="key">The key to add.</param>
/// <param name="item">The item to add.</param>
/// <returns>The instance of the <see cref="ObservableGroup{TKey, TValue}"/> which will receive the value. It will either be an existing group or a new group.</returns>
public static ObservableGroup<TKey, TValue> AddItem<TKey, TValue>(
this ObservableGroupedCollection<TKey, TValue> source,
TKey key,
TValue item)
{
var existingGroup = source.FirstOrDefault(group => GroupKeyPredicate(group, key));
if (existingGroup is null)
{
existingGroup = new ObservableGroup<TKey, TValue>(key);
source.Add(existingGroup);
}
existingGroup.Add(item);
return existingGroup;
}
/// <summary>
/// Remove the first occurrence of the group with <paramref name="key"/> from the <paramref name="source"/> grouped collection.
/// It will not do anything if the group does not exist.
/// </summary>
/// <typeparam name="TKey">The type of the group key.</typeparam>
/// <typeparam name="TValue">The type of the items in the collection.</typeparam>
/// <param name="source">The source <see cref="ObservableGroupedCollection{TKey, TValue}"/> instance.</param>
/// <param name="key">The key of the item to remove.</param>
public static void RemoveGroup<TKey, TValue>(
this ObservableGroupedCollection<TKey, TValue> source,
TKey key)
{
var index = 0;
foreach (var group in source)
{
if (GroupKeyPredicate(group, key))
{
source.RemoveAt(index);
return;
}
index++;
}
}
/// <summary>
/// Remove the first <paramref name="item"/> from the first group with <paramref name="key"/> from the <paramref name="source"/> grouped collection.
/// It will not do anything if the group or the item does not exist.
/// </summary>
/// <typeparam name="TKey">The type of the group key.</typeparam>
/// <typeparam name="TValue">The type of the items in the collection.</typeparam>
/// <param name="source">The source <see cref="ObservableGroupedCollection{TKey, TValue}"/> instance.</param>
/// <param name="key">The key of the item to remove.</param>
/// <param name="item">The item to remove.</param>
/// <param name="removeGroupIfEmpty">If true (default value), the group will be removed once it becomes empty.</param>
public static void RemoveItem<TKey, TValue>(
this ObservableGroupedCollection<TKey, TValue> source,
TKey key,
TValue item,
bool removeGroupIfEmpty = true)
{
var index = 0;
foreach (var group in source)
{
if (GroupKeyPredicate(group, key))
{
group.Remove(item);
if (removeGroupIfEmpty && group.Count == 0)
{
source.RemoveAt(index);
}
return;
}
index++;
}
}
/// <summary>
/// Remove the item at <paramref name="index"/> from the first group with <paramref name="key"/> from the <paramref name="source"/> grouped collection.
/// It will not do anything if the group or the item does not exist.
/// </summary>
/// <typeparam name="TKey">The type of the group key.</typeparam>
/// <typeparam name="TValue">The type of the items in the collection.</typeparam>
/// <param name="source">The source <see cref="ObservableGroupedCollection{TKey, TValue}"/> instance.</param>
/// <param name="key">The key of the item to remove.</param>
/// <param name="index">The index of the item to remove in the group.</param>
/// <param name="removeGroupIfEmpty">If true (default value), the group will be removed once it becomes empty.</param>
public static void RemoveItemAt<TKey, TValue>(
this ObservableGroupedCollection<TKey, TValue> source,
TKey key,
int index,
bool removeGroupIfEmpty = true)
{
var groupIndex = 0;
foreach (var group in source)
{
if (GroupKeyPredicate(group, key))
{
group.RemoveAt(index);
if (removeGroupIfEmpty && group.Count == 0)
{
source.RemoveAt(groupIndex);
}
return;
}
groupIndex++;
}
}
private static bool GroupKeyPredicate<TKey, TValue>(ObservableGroup<TKey, TValue> group, TKey expectedKey)
=> EqualityComparer<TKey>.Default.Equals(group.Key, expectedKey);
}
}