[英]Testing for value equality between two interface instances in c#?
So I have an interface, lets call it IInterface. 所以我有一个接口,我们称之为IInterface。
public interface IInterface : IEquatable<IInterface>
{
string Name { get; set; }
int Number { get; }
Task<bool> Update();
}
Then I try and implement the interface in Implementation. 然后我尝试在Implementation中实现接口。
public bool Equals(IInterface other)
{
if (other == null) return false;
return (this.Name.Equals(other.Name) && this.Number.Equals(other.Number));
}
public override int GetHashCode()
{
return this.Number.GetHashCode();
}
public override bool Equals(object obj)
{
var other = obj as IInterface ;
return other != null && Equals(other);
}
public static bool operator ==(Implementation left, IInterface right)
{
if (ReferenceEquals(left, right)) return true;
if (ReferenceEquals(left, null)) return false;
return left.Equals(right);
}
public static bool operator !=(Implementation left, IInterface right)
{
return !(left == right);
}
The problem I am running into is in a setter: 我遇到的问题是在setter中:
public IInterface MyIntf
{
get { return _myIntf; }
set
{
if (_myIntf == value) { return; }
_myIntf = value;
}
Intellisense is showing that the equality test there is testing the references only and treating both left and right as objects. Intellisense显示,那里的相等测试只测试引用并将左右两个都视为对象。 I assume this is because there is no operator overload for ==(IInterface left, IInterface right). 我假设这是因为==(IInterface left,IInterface right)没有运算符重载。 Of course, I cannot actually implement that function because == requires one of the sides to match the type of the implementing class. 当然,我实际上无法实现该函数,因为==要求其中一方与实现类的类型相匹配。 How does one properly make sure two interfaces can be checked for equality against each other? 如何正确确保可以检查两个接口是否相互平等?
Update 更新
Got it, you cannot implement == for an interface. 知道了,你不能为接口实现==。 I will use Equals. 我会使用Equals。 Thanks everyone. 感谢大家。
Use Equals
instead of ==
: 使用Equals
而不是==
:
public IInterface MyIntf
{
get { return _myIntf; }
set
{
if (_myIntf.Equals(value)) { return; }
_myIntf = value;
}
}
You should explicitly call Equals
: 你应该明确地调用Equals
:
if (_myIntf != null && _myIntf.Equals(value)) { return; }
Implementing IEquatable<T>
does not impact the ==
operator. 实现IEquatable<T>
不会影响==
运算符。
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