相关疑难解决方法(0)

有两个不可变类Base和Derived(派生自Base)我想定义Equality这样

• 平等总是多态的 - ((Base)derived1).Equals((Base)derived2)即将调用Derived.Equals

• 运营商==和!=将调用Equals,而不是ReferenceEquals(值相等)

我做了什么:

class Base: IEquatable<Base> {
  public readonly ImmutableType1 X;
  readonly ImmutableType2 Y;

  public Base(ImmutableType1 X, ImmutableType2 Y) { 
    this.X = X; 
    this.Y = Y; 
  }

  public override bool Equals(object obj) {
    if (object.ReferenceEquals(this, obj)) return true;
    if (obj is null || obj.GetType()!=this.GetType()) return false;

    return obj is Base o 
      && X.Equals(o.X) && Y.Equals(o.Y);
  }

  public override int GetHashCode() => HashCode.Combine(X, Y);

  // boilerplate
  public bool …