Overloading = operator in C#

  • Thread starter Thread starter Alberto Bencivenni
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Alberto Bencivenni

Hi All,


I know there is no way to overload the = operator in C# for a class
object: you can only get something similar using the (myClass)
myClass.Clone(); method or creating a copy constructor.

The question is: Does a more elegant way to do this exist? (I am
thinking to how elegant is the operator = overloading in standard C++)

Thanks,

Alberto
 
Alberto said:
Hi All,


I know there is no way to overload the = operator in C# for a class
object: you can only get something similar using the (myClass)
myClass.Clone(); method or creating a copy constructor.
Click to expand...

It sounds like you want value-type semantics. If so, you want a struct.

Alun Harford
 
Alberto Bencivenni said:
I know there is no way to overload the = operator in C# for a class
object: you can only get something similar using the (myClass)
myClass.Clone(); method or creating a copy constructor.

The question is: Does a more elegant way to do this exist? (I am
thinking to how elegant is the operator = overloading in standard C++)
Click to expand...

You've described how you'd achieve some effect in C++, but not really
stated what the goal is. *Why* do you want to overload the = operator?
What are the benefits? (Think particularly carefully of the
readability, especially when C# developers are used to reference
assignment semantics.)
 
Hi All,

thanks for your answers.

We currently use a Point struct but need to extend it someway and
composition is not an option (in terms of memory comsumption), so we
need a class.

By the way classes don't allow easy = operator and for a Point
paradigm is a big lack.

Let me know what you think.

Thanks,

Alberto
 
Alberto Bencivenni said:
thanks for your answers.

We currently use a Point struct but need to extend it someway and
composition is not an option (in terms of memory comsumption), so we
need a class.
Click to expand...

How would composition with structs create more memory consumption?
By the way classes don't allow easy = operator and for a Point
paradigm is a big lack.

Let me know what you think.
Click to expand...

I think you'd be a lot better off by making your type immutable, with
methods which produce a new instance with a changed value - the same
sort of design as System.String.

Copying the *contents* every time you used the assignment operator
would not only be completely counterintuitive to other .NET
programmers, but it would also be expensive in terms of memory.
 
How would composition with structs create more memory consumption?
Click to expand...

Suppose you have a Point(x,y) but in a few cases you need
Point(x,y,r,g,b) and you have an array of 1,000,000 points. Dows it
worth to make a struct that has 5 members?
Copying the *contents* every time you used the assignment operator
would not only be completely counterintuitive to other .NET
programmers, but it would also be expensive in terms of memory.
Click to expand...

I completely agree with your thought, although thinking about a Point
object that cannot be simply assigned with = operator sounds weird to
me.

Thanks,

Alberto
 
Alberto Bencivenni said:
Suppose you have a Point(x,y) but in a few cases you need
Point(x,y,r,g,b) and you have an array of 1,000,000 points. Dows it
worth to make a struct that has 5 members?
Click to expand...

I'd have three structs: Point, Color, and ColoredPoint. The idea that
I'd have a million points and *some* would be coloured but some
wouldn't is of course feasible, but it's pretty rare. In that
particular case it does make sense to use classes instead - but I'd
consider whether an alternative data structure overlaying the whole
thing might not make even more sense. Obviously you know more about
your situation than I do - I'm just saying that when you have unusual
requirements, it can be worth trying to think of other ways of looking
at the problem.
I completely agree with your thought, although thinking about a Point
object that cannot be simply assigned with = operator sounds weird to
me.
Click to expand...

And an immutable class will do exactly that. The reference can be
assigned with the = operator with no problems at all.
 
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