49 lines
1.4 KiB
C#
49 lines
1.4 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Linq;
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namespace Hncore.Infrastructure.EntitiesExtension
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{
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public class CommonEqualityComparer<T, V> : IEqualityComparer<T>
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{
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private Func<T, V> keySelector;
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private IEqualityComparer<V> comparer;
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public CommonEqualityComparer(Func<T, V> keySelector, IEqualityComparer<V> comparer)
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{
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this.keySelector = keySelector;
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this.comparer = comparer;
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}
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public CommonEqualityComparer(Func<T, V> keySelector)
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: this(keySelector, EqualityComparer<V>.Default)
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{ }
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public bool Equals(T x, T y)
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{
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return comparer.Equals(keySelector(x), keySelector(y));
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}
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public int GetHashCode(T obj)
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{
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return comparer.GetHashCode(keySelector(obj));
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}
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}
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/// <summary>
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/// 扩展类
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/// </summary>
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public static class DistinctExtensions
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{
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public static IEnumerable<T> Distinctx<T, V>(this IEnumerable<T> source, Func<T, V> keySelector)
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{
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return source.Distinct(new CommonEqualityComparer<T, V>(keySelector));
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}
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public static IEnumerable<T> Distinctx<T, V>(this IEnumerable<T> source, Func<T, V> keySelector, IEqualityComparer<V> comparer)
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{
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return source.Distinct(new CommonEqualityComparer<T, V>(keySelector, comparer));
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}
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}
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}
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