对象Equals相等性比较的通用实现

最近编码的过程中，使用了对象本地内存缓存，缓存用了Dictionary<string,object>, ConcurrentDictionary<string,oject>,还可以是MemoryCache(底层基于Hashtable)。使用缓存，肯定要处理数据变化缓存同步的问题。如何比较数据的变化，演进为新的内存对象数据和已有内存对象数据的相等性比较！

对象的Equals相等性比较，百度、google会有一大堆实现，几个重点的点：

1. 实现接口IEquatable<T>

https://msdn.microsoft.com/en-us/library/ms131190(v=vs.110).aspx

2.重写bool Equals(object other)方法和 int GetHashCode()方法

http://stackoverflow.com/questions/2734914/whats-the-difference-between-iequatable-and-just-overriding-object-equals

这里直接贴出来一个通用实现，分享给大家：

 /// <summary>
    /// 流控事件
    /// </summary>
    [Serializable]
    public class FlowControlEvent: IEquatable<FlowControlEvent>
    {
        public static readonly string Global = "Global";

        /// <summary>
        /// 标识
        /// </summary>
        public string ID { get; set; }

        /// <summary>
        /// 流控策略名称
        /// </summary>
        public string StrategyName { get; set; }

        /// <summary>
        /// 是否手工触发
        /// </summary>
        public bool IsManuelTrigger { get; set; }

        /// <summary>
        /// 触发时间
        /// </summary>
        public DateTime TriggerTime { get; set; }        

        /// <summary>
        /// 流控策略
        /// </summary>
        public FlowControlStrategy Strategy { get; set; }

        /// <summary>
        /// 持续时间，单位s
        /// </summary>
        public long Duration { get; set; }

        //是否启用
        private bool isEnable = true;

        /// <summary>
        /// 是否启用
        /// </summary>
        public bool IsEnable
        {
            get
            {
                return isEnable;
            }
            set
            {
                isEnable = value;
            }
        }

        /// <summary>
        /// 是否使用中
        /// </summary>
        public bool IsUsing
        {
            get
            {
                if (IsEnable == false) return false;
                if (IsManuelTrigger)
                {
                    if (Duration == long.MaxValue)
                    {
                        return true;
                    }
                    else
                    {
                        var span = DateTime.Now - TriggerTime;
                        if (span.TotalSeconds > Duration)
                            return false;
                        else
                            return true;
                    }
                }
                else
                {
                    return true;
                }
            }
        }

        /// <summary>
        /// 创建时间
        /// </summary>
        public DateTime CreateTime { get; set; }

        /// <summary>
        /// 创建人
        /// </summary>
        public string Creator { get; set; }

        /// <summary>
        /// 最后修改时间
        /// </summary>
        public DateTime LastModifyTime { get; set; }

        /// <summary>
        /// 最后修改人
        /// </summary>
        public string LastModifier { get; set; }

        /// <summary>
        /// 相等性比较
        /// </summary>
        /// <param name="other">要比较的对象</param>
        /// <returns>true 相等 false 不相等</returns>
        public override bool Equals(object other)
        {
            if (ReferenceEquals(null, other)) return false;
            if (ReferenceEquals(this, other)) return true;
            if (other.GetType() != this.GetType()) return false;

            return Equals((FlowControlEvent)other);
        }

        /// <summary>
        /// 流控事件是否等于同一类型的另一个流控事件
        /// </summary>
        /// <param name="other">同一类型的另一个流控事件</param>
        /// <returns>true 相等 false 不相等</returns>
        public bool Equals(FlowControlEvent other)
        {
            if (other == null)
                return false;
            if (!string.Equals(this.ID , other.ID) || this.IsEnable != other.IsEnable || this.Duration!= other.Duration
                || !string.Equals(this.StrategyName, other.StrategyName)||this.TriggerTime!= other.TriggerTime)
                return false;

            return true;
        }

        /// <summary>
        /// 重载GetHashCode方法
        /// </summary>
        /// <returns>HashCode</returns>
        public override int GetHashCode()
        {
            unchecked
            {
                var result = 0;
                result = (result * 397) ^ ID.GetHashCode();
                result = (result * 397) ^ IsEnable.GetHashCode();
                result = (result * 397) ^ Duration.GetHashCode();
                result = (result * 397) ^ StrategyName.GetHashCode();
                result = (result * 397) ^ TriggerTime.GetHashCode();
                return result;
            }
        }
    }

周国庆

2017/4/25