I have a C++/CLI class definition where I'm trying to get Equality testing to be Value based rahter than Reference (similar to the behavior of String). The following definitions work:
namespace MyCode
{
public ref class MyClass
{
public:
MyClass();
bool operator==(MyClass^ obj) { return Equals(obj); }
bool operator!=(MyClass^ obj) { return !Equals(obj); }
virtual bool Equals(MyClass^ obj);
virtual bool Equals(System::Object^ obj) override;
virtual int GetHashCode() override;
};
}
However, my company is now requiring (and rightly so) that all code needs to conform to the Code Analysis rules. Code analysis consistently reports two warnings on the above class:
CA2226 : Microsoft.Usage : Since ''MyClass'' redefines op开发者_Go百科erator '==', it should also redefine operator '!='.
CA2226 : Microsoft.Usage : Since ''MyClass'' redefines operator '!=', it should also redefine operator '=='.
The Microsoft documentation on warning CA2226 makes it clear that this is an important warning and should not be suppressed - but what else can I do?
I'm looking for a way (if possible) to 'fix' the code in order to remove this warning. Is that possible, or do I just need to suppress it?
For a ref class
, you're supposed to implement operator==(MyClass^ left, MyClass^ right)
as a static member function, this is the one other .NET languages will find.
Your current implementation defines operator==(MyClass%, MyClass^ right)
instead, which is unusual.
Note that you can't rely on left != nullptr
, you need to test ReferenceEquals(left, nullptr)
.
This is a .NET implementation detail. Having instance operator overloads is a C++ feature, the code analyzer chokes on it. The .NET way is to have operator overloads as static functions. Notably C# requires this. Solve your problem similar to this:
static bool operator==(MyClass^ lhs, MyClass^ rhs) { return lhs->Equals(rhs); }
static bool operator!=(MyClass^ lhs, MyClass^ rhs) { return !lhs->Equals(rhs); }
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