/// <summary>
/// 通过委托实现<see cref="IEqualityComparer{Obj}"/>，
/// 它从<typeparamref name="Obj"/>对象中提取键，
/// 然后逐个比较它们，作为判断相等的标准
/// </summary>
/// <typeparam name="Obj">要比较的对象类型</typeparam>
/// <param name="getKey">从<typeparamref name="Obj"/>对象中提取键的委托</param>
/// <returns></returns>
public static IEqualityComparer <Obj> EqualityComparer <Obj>(params Func <Obj, object>[] getKey)
{
getKey.AnyCheck("用来获取键的委托");
return(EqualityComparer <Obj>(
(x, y) => getKey.All(del => Equals(del(x), del(y))),
x => ToolEqual.CreateHash(getKey.Select(del => del(x)).ToArray())));
}
/// <summary>
/// 使用指定的参数初始化对象
/// </summary>
/// <param name="equals">这个委托用于执行相等比较</param>
/// <param name="getHashCode">这个委托用于计算哈希值</param>
public EqualityComparer(Func <Obj, Obj, bool> equals, Func <Obj, int> getHashCode)
{
this.EqualsDelegate = (x, y) => ToolEqual.JudgeNull(x, y) ?? equals(x !, y !);
this.GetHashCodeDelegate = x => x is null ? 0 : getHashCode(x);
}