How To overload =

[Harry J. Smith]

How do you overload the = operator?

public static MultiUI operator = (MultiUI left, MultiUI right)

{

return right;

}

gives an error of "overloadab le binary operator expected"



-Harry

[cody]

Re: How To overload =

You cannot overload operator=, but you can overload the type conversion
operator.
According to your example what sense would it make to overload operator=
which only assign one objects of type T to another object with exact the
same type?

--
cody

[Freeware, Games and Humor]
www.deutronium.de.vu || www.deutronium.tk
"Harry J. Smith" <hjsmith@ix.net com.com> schrieb im Newsbeitrag
news:A6%Jc.5650 $Qu5.4543@newsr ead2.news.pas.e arthlink.net...[color=blue]
> How do you overload the = operator?
>
> public static MultiUI operator = (MultiUI left, MultiUI right)
>
> {
>
> return right;
>
> }
>
> gives an error of "overloadab le binary operator expected"
>
>
>
> -Harry
>
>[/color]

[Daniel Billingsley]

Re: How To overload =

Yeah, what he said. :)

I thought I needed to overload = to create my own string-like class until I
read this article where I learned overloading the type conversion did the
trick.

http://www.c-sharpcorner.com/1/SuperStringMG.asp

"cody" <please_dont.sp am.deutronium@g mx.de> wrote in message
news:ei1%23Vw6a EHA.2816@TK2MSF TNGP11.phx.gbl. ..[color=blue]
> You cannot overload operator=, but you can overload the type conversion
> operator.
> According to your example what sense would it make to overload operator=
> which only assign one objects of type T to another object with exact the
> same type?
>[/color]

[Harry J. Smith]

Re: How To overload =

When you do a = b, where a and b are two objects, only the pointer to b is copied so a and b are the same object. The disassembly
shows:

a = b;

000000d7 mov edi,dword ptr [ebp-18h]

I wanted a function to copy all of the fields of b to a and have two objects whose fields are currently equal. I can do this with a
function like SetTo(b, a), but I wanted to do it with the = operator. This may be a bad idea because if you could do it you would
loose the copy pointer method.

-Harry

"cody" <please_dont.sp am.deutronium@g mx.de> wrote in message news:ei1%23Vw6a EHA.2816@TK2MSF TNGP11.phx.gbl. ..[color=blue]
> You cannot overload operator=, but you can overload the type conversion
> operator.
> According to your example what sense would it make to overload operator=
> which only assign one objects of type T to another object with exact the
> same type?
>
> --
> cody
>
> [Freeware, Games and Humor]
> www.deutronium.de.vu || www.deutronium.tk
> "Harry J. Smith" <hjsmith@ix.net com.com> schrieb im Newsbeitrag
> news:A6%Jc.5650 $Qu5.4543@newsr ead2.news.pas.e arthlink.net...[color=green]
> > How do you overload the = operator?
> >
> > public static MultiUI operator = (MultiUI left, MultiUI right)
> >
> > {
> >
> > return right;
> >
> > }
> >
> > gives an error of "overloadab le binary operator expected"
> >
> >
> >
> > -Harry
> >
> >[/color]
>
>[/color]

[Jon Skeet [C# MVP]]

Re: How To overload =

Harry J. Smith <hjsmith@ix.net com.com> wrote:[color=blue]
> When you do a = b, where a and b are two objects, only the pointer to
> b is copied so a and b are the same object. The disassembly
> shows:
>
> a = b;
>
> 000000d7 mov edi,dword ptr [ebp-18h]
>
> I wanted a function to copy all of the fields of b to a and have two
> objects whose fields are currently equal. I can do this with a
> function like SetTo(b, a), but I wanted to do it with the = operator.
> This may be a bad idea because if you could do it you would
> loose the copy pointer method.[/color]

So you want value type semantics for assignment. Do you need reference
type semantics elsewhere, or could you just make your type a reference
type?

Don't forget that assignments effectively happen elsewhere - what would
you want to happen when someone passed a parameter? Should that make a
new object or not?

--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too

[Stu Smith]

Re: How To overload =


"Jon Skeet [C# MVP]" <skeet@pobox.co m> wrote in message
news:MPG.1b6349 3faf3b7bca98aef a@msnews.micros oft.com...[color=blue]
> Harry J. Smith <hjsmith@ix.net com.com> wrote:[color=green]
> > When you do a = b, where a and b are two objects, only the pointer to
> > b is copied so a and b are the same object. The disassembly
> > shows:
> >
> > a = b;
> >
> > 000000d7 mov edi,dword ptr [ebp-18h]
> >
> > I wanted a function to copy all of the fields of b to a and have two
> > objects whose fields are currently equal. I can do this with a
> > function like SetTo(b, a), but I wanted to do it with the = operator.
> > This may be a bad idea because if you could do it you would
> > loose the copy pointer method.[/color]
>
> So you want value type semantics for assignment. Do you need reference
> type semantics elsewhere, or could you just make your type a reference
> type?[/color]

Didn't you mean to say "...or could you just make your type a _value_ type?"
[color=blue]
>
> Don't forget that assignments effectively happen elsewhere - what would
> you want to happen when someone passed a parameter? Should that make a
> new object or not?
>
> --
> Jon Skeet - <skeet@pobox.co m>
> http://www.pobox.com/~skeet
> If replying to the group, please do not mail me too[/color]

[Jon Skeet [C# MVP]]

Re: How To overload =

Stu Smith <stuarts@nosp am-digita.com> wrote:[color=blue][color=green]
> > So you want value type semantics for assignment. Do you need reference
> > type semantics elsewhere, or could you just make your type a reference
> > type?[/color]
>
> Didn't you mean to say "...or could you just make your type a _value_ type?"[/color]

Yup. Oops.

--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too