C#判等對象能否相等的辦法匯總

C#判等對象能否相等的辦法匯總。本站提示廣大學習愛好者：（C#判等對象能否相等的辦法匯總）文章只能為提供參考，不一定能成為您想要的結果。以下是C#判等對象能否相等的辦法匯總正文

本文以實例情勢展現了C#判等對象能否相等的經常使用辦法，異常適用，可供年夜家參考自創之用。詳細剖析以下：

1、斷定相等的3個辦法

1.實例辦法

public virtual bool Equals(object obj) 
{ 
  return RuntimeHelpers.Equals(this, obj); 
}

2.比擬值類型靜態辦法

public static bool Equals(object objA, object objB) 
{ 
  return ((objA == objB) || (((objA != null) && (objB != null)) && objA.Equals(objB))); 
}

3.比擬援用類型靜態辦法

public static bool ReferenceEquals(object objA, object objB) 
{ 
  return (objA == objB); 
}

2、斷定援用類型能否相等

  class Program 
  { 
    static void Main(string[] args) 
    { 
      Team t1 = new Team("馬爾切洛·裡皮"); 
      Team t2 = new Team("馬爾切洛·裡皮"); 
      var result = (t1 == t2); 
      Console.WriteLine(result); 
      result = t1.Equals(t2); 
      Console.WriteLine(result); 
      Console.ReadKey(); 
    } 
  }
 
  public class Team 
  { 
    public string _coach = string.Empty;
 
    public Team(string coach) 
    { 
      this._coach = coach; 
    } 
  }
 
  public struct TeamStruct 
  { 
    public string _coach;
 
    public TeamStruct(string coach) 
    { 
      this._coach = coach; 
    } 
  }
 

運轉成果：

false
false

剖析：援用類型比擬的是援用地址，因為t1和t2指向分歧的對象實例，所以dou都前往false。  

3、斷定值類型能否相等

1.值類型斷定辦法

派生於System.ValueType，對System.Object中的虛辦法Equals(object obj)停止了重寫

public override bool Equals(object obj) 
{ 
  if (obj == null) 
  { 
    return false; 
  } 
  RuntimeType type = (RuntimeType) base.GetType(); 
  RuntimeType type2 = (RuntimeType) obj.GetType(); 
  if (type2 != type) //比擬兩個對象能否是統一類型 
  { 
    return false; 
  } 
  object a = this; 
  if (CanCompareBits(this)) //對象成員假如存在關於堆的援用前往false 
  { 
    return FastEqualsCheck(a, obj); 
  } 
  //反射獲得值類型的一切字段 
  FieldInfo[] fields = type.GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance); 
  for (int i = 0; i < fields.Length; i++) //遍歷字段，對各個字段停止比擬 
  { 
    object obj3 = ((RtFieldInfo) fields[i]).UnsafeGetValue(a); 
    object obj4 = ((RtFieldInfo) fields[i]).UnsafeGetValue(obj); 
    if (obj3 == null) 
    { 
      if (obj4 != null) 
      { 
        return false; 
      } 
    } 
    else if (!obj3.Equals(obj4)) 
    { 
      return false; 
    } 
  } 
  return true; 
}

2.用==斷定能否相等

    static void Main(string[] args) 
    { 
      TeamStruct ts1 = new TeamStruct("馬爾切洛·裡皮"); 
      TeamStruct ts2 = ts1; 
      var result = (ts1 == ts2); 
      Console.WriteLine(result); 
      Console.ReadKey(); 
    }

湧現編譯毛病。緣由是值類型不克不及用==停止斷定。

3.用Equals()實例辦法斷定能否相等

    static void Main(string[] args) 
    { 
      TeamStruct ts1 = new TeamStruct("馬爾切洛·裡皮"); 
      TeamStruct ts2 = ts1; 
      var result = ts1.Equals(ts2); 
      Console.WriteLine(result); 
      Console.ReadKey(); 
    }

前往true。

可見，假如值類型的字段相等，那就相等。

    static void Main(string[] args) 
    { 
      TeamStruct ts1 = new TeamStruct("馬爾切洛·裡皮"); 
      TeamStruct ts2 = ts1; 
      ts2._coach = "高洪波"; 
      var result = ts1.Equals(ts2); 
      Console.WriteLine(result); 
      Console.ReadKey(); 
    }

前往false,固然，值類型的字段有不相等，就會全部不相等。

4.斷定龐雜值類型能否相等

即值類型中包括援用類型和值類型。

  class Program 
  { 
    static void Main(string[] args) 
    { 
      Team t = new Team("馬爾切洛·裡皮"); 
      TeamStruct ts = new TeamStruct("馬爾切洛·裡皮");
 
      NationalTeam nt1 = new NationalTeam(t, ts); 
      NationalTeam nt2 = nt1; 
      var result = nt1.Equals(nt2); 
      Console.WriteLine(result); 
      Console.ReadKey(); 
    } 
  }
 
  public class Team 
  { 
    public string _coach = string.Empty;
 
    public Team(string coach) 
    { 
      this._coach = coach; 
    } 
  }
 
  public struct TeamStruct 
  { 
    public string _coach;
 
    public TeamStruct(string coach) 
    { 
      this._coach = coach; 
    } 
  }
 
  public struct NationalTeam 
  { 
    public Team _team; 
    public TeamStruct _structTeam;
 
    public NationalTeam(Team team, TeamStruct structTeam) 
    { 
      this._team = team; 
      this._structTeam = structTeam; 
    } 
  }
 

前往true，會遍歷比擬援用類型成員和值類型成員。在nt1和nt2中，類型為Team的援用類型成員_team指向統一個對象實例，  類型為TeamStruct的值類型成員_structTeam相等，一切全部前往。以下圖所示：