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://*.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 = ;
                 result = (result * ) ^ ID.GetHashCode();
                 result = (result * ) ^ IsEnable.GetHashCode();
                 result = (result * ) ^ Duration.GetHashCode();
                 result = (result * ) ^ StrategyName.GetHashCode();
                 result = (result * ) ^ TriggerTime.GetHashCode();
                 return result;
             }
         }
     }

周国庆

2017/4/25