const or readonly

[Axel Dahmen]

Hi,

can someone please enlighten me on the difference between a "const" and a
"readonly" declaration?

TIA,
Axel Dahmen

[Jon Skeet [C# MVP]]

Axel Dahmen <NO*****@NoOneKnows.invalid> wrote:

can someone please enlighten me on the difference between a "const" and a
"readonly" declaration?

If a field is "const", anything which refers to the field has the value
of the constant placed into the IL - there is no runtime reference to
it. This has one potentially nasty side-effect - if you change the
value of a const field in one assembly (at compile-time, I mean) then
any other assemblies which need to see the "new" value need to be
recompiled - they won't try to "get" the value from the originating
assembly at runtime.

Consts are probably more performant (although it's unlikely to be
significant), but can only be applied to a limited range of types.

Of course, consts are also limited to those values which are known at
compile-time.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Marina]

readonly can be set to a value in the constructor. Const cannot - its value
must be provided inline with the declaration.

"Axel Dahmen" <NO*****@NoOneKnows.invalid> wrote in message
news:eM**************@TK2MSFTNGP15.phx.gbl...

Hi,

can someone please enlighten me on the difference between a "const" and a
"readonly" declaration?

TIA,
Axel Dahmen