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：

  1  /// <summary>2     /// 流控事件3     /// </summary>4     [Serializable]5     public class FlowControlEvent: IEquatable<FlowControlEvent>6     {7         public static readonly string Global = "Global";8 9         /// <summary>10         /// 标识11         /// </summary>12         public string ID { get; set; }13 14         /// <summary>15         /// 流控策略名称16         /// </summary>17         public string StrategyName { get; set; }18 19         /// <summary>20         /// 是否手工触发21         /// </summary>22         public bool IsManuelTrigger { get; set; }23 24         /// <summary>25         /// 触发时间26         /// </summary>27         public DateTime TriggerTime { get; set; }        28 29         /// <summary>30         /// 流控策略31         /// </summary>32         public FlowControlStrategy Strategy { get; set; }33 34         /// <summary>35         /// 持续时间，单位s36         /// </summary>37         public long Duration { get; set; }38 39         //是否启用40         private bool isEnable = true;41 42         /// <summary>43         /// 是否启用44         /// </summary>45         public bool IsEnable46         {47             get48             {49                 return isEnable;50             }51             set52             {53                 isEnable = value;54             }55         }56 57         /// <summary>58         /// 是否使用中59         /// </summary>60         public bool IsUsing61         {62             get63             {64                 if (IsEnable == false) return false;65                 if (IsManuelTrigger)66                 {67                     if (Duration == long.MaxValue)68                     {69                         return true;70                     }71                     else72                     {73                         var span = DateTime.Now - TriggerTime;74                         if (span.TotalSeconds > Duration)75                             return false;76                         else77                             return true;78                     }79                 }80                 else81                 {82                     return true;83                 }84             }85         }86 87         /// <summary>88         /// 创建时间89         /// </summary>90         public DateTime CreateTime { get; set; }91 92         /// <summary>93         /// 创建人94         /// </summary>95         public string Creator { get; set; }96 97         /// <summary>98         /// 最后修改时间99         /// </summary>
100         public DateTime LastModifyTime { get; set; }
101 
102         /// <summary>
103         /// 最后修改人
104         /// </summary>
105         public string LastModifier { get; set; }
106 
107         /// <summary>
108         /// 相等性比较
109         /// </summary>
110         /// <param name="other">要比较的对象</param>
111         /// <returns>true 相等 false 不相等</returns>
112         public override bool Equals(object other)
113         {
114             if (ReferenceEquals(null, other)) return false;
115             if (ReferenceEquals(this, other)) return true;
116             if (other.GetType() != this.GetType()) return false;
117 
118             return Equals((FlowControlEvent)other);
119         }
120 
121         /// <summary>
122         /// 流控事件是否等于同一类型的另一个流控事件
123         /// </summary>
124         /// <param name="other">同一类型的另一个流控事件</param>
125         /// <returns>true 相等 false 不相等</returns>
126         public bool Equals(FlowControlEvent other)
127         {
128             if (other == null)
129                 return false;
130             if (!string.Equals(this.ID , other.ID) || this.IsEnable != other.IsEnable || this.Duration!= other.Duration
131                 || !string.Equals(this.StrategyName, other.StrategyName)||this.TriggerTime!= other.TriggerTime)
132                 return false;
133 
134             return true;
135         }
136 
137         /// <summary>
138         /// 重载GetHashCode方法
139         /// </summary>
140         /// <returns>HashCode</returns>
141         public override int GetHashCode()
142         {
143             unchecked
144             {
145                 var result = 0;
146                 result = (result * 397) ^ ID.GetHashCode();
147                 result = (result * 397) ^ IsEnable.GetHashCode();
148                 result = (result * 397) ^ Duration.GetHashCode();
149                 result = (result * 397) ^ StrategyName.GetHashCode();
150                 result = (result * 397) ^ TriggerTime.GetHashCode();
151                 return result;
152             }
153         }
154     }

周国庆

2017/4/25