C#中==(双等于号)与equals()区别详解

#region 值类型判断
int i = 10;
int j = 10;
Console.WriteLine($"双等于号判断结果为：{(i == j)}");
Console.WriteLine($"Equals判断结果为：{i.Equals(j)}");
 
#endregion

#region 引用类型中String比较
Console.WriteLine("----------------我是分割线-----------------------");
string str1 = "abd";
string str2 = "abd";
Console.WriteLine($"双等于号判断结果为：{(str1 == str2)}");
Console.WriteLine($"Equals判断结果为：{str1.Equals(str2)}");
#endregion

//
// 摘要:
//     Determines whether two specified strings have the same value.
//
// 参数:
//   a:
//     The first string to compare, or null.
//
//   b:
//     The second string to compare, or null.
//
// 返回结果:
//     true if the value of a is the same as the value of b; otherwise, false.
public static bool operator ==(String? a, String? b);
 
 
//
// 摘要:
//     Determines whether this instance and another specified System.String object have
//     the same value.
//
// 参数:
//   value:
//     The string to compare to this instance.
//
// 返回结果:
//     true if the value of the value parameter is the same as the value of this instance;
//     otherwise, false. If value is null, the method returns false.
public bool Equals(String? value);

#region 引用类型中自定义类型t比较
Console.WriteLine("----------------我是分割线-----------------------");
Car car1 = new Car()
{
    Age = 4,
    Color = "Green"
};
Car car2 = new Car()
{
    Age = 4,
    Color = "Green"
};
 
Console.WriteLine($"双等于号判断结果为:{(car1 == car2)}");
Console.WriteLine($"Equals判断结果为：{car1.Equals(car2)}");

public class TwoDPoint : System.Object
    {
        public readonly int x, y;

        public TwoDPoint(int x, int y) 
        {
            this.x = x;
            this.y = y;
        }

        public override bool Equals(System.Object obj)
        {
            if (obj == null)
            {
                return false;
            }

            TwoDPoint p = obj as TwoDPoint;
            if ((System.Object)p == null)
            {
                return false;
            }
            return (x == p.x) && (y == p.y);
        }

        public bool Equals(TwoDPoint p)
        {
            if ((object)p == null)
            {
                return false;
            }

            return (x == p.x) && (y == p.y);
        }

        public override int GetHashCode()
        {
            return x ^ y;
        }


    }

#region 引用类型中自定义类型t比较
  Console.WriteLine("----------------我是分割线-----------------------");

  TwoDPoint twoDPoint1 = new TwoDPoint(4, 8);
  TwoDPoint twoDPoint2 = new TwoDPoint(4, 8);

  Console.WriteLine($"双等于号判断结果为:{(twoDPoint1 == twoDPoint2)}");
  Console.WriteLine($"Equals重写后判断结果为：{twoDPoint1.Equals(twoDPoint2)}");
  #endregion