In the C# , I want to change the object only after the user click the
"Submit" button , so I first new an object and use the "=" to get the object
in memory , I found that the operation "=" only get a reference to the
target object which I want to copy , how can I do copy it ?
Nov 17 '05
11  5189 
On Sat, 11 Jun 2005 10:34:23 +0100, Mark Broadbent wrote: Really not sure what you are trying to say?
:)
That you are funny?
You'll also note that I said "referencin g another instance you
are effectively making a copy" in this string scenario. What I mean by
'effectively' is that even *if* s1 did point to s2 at that time of
assignment, the exact moment that a change is made to either s1 or s2 they
would point to different instances due to the immutable rule (as my simple
example shows).
The mention of "s2 = s1;"
'effectively' making a copy would lead one to think that the subsequent
's1 = "two" ; '
makes the initial object pointed to by s1 eligible for garbage collection,
whereas I should think that it is not because it is being pointed to by s2.
to put it simply, the value that is referenced by a string variable is
protected from a change from another.
I think it's just more confusing to bring up 'effective copies' to
explain that. String is immutable. The content of the object it references
cannot be changed. Period.
What's up with the new school of thought of some need for protection from
"another" ? heh.
Rico.
Not really sure why you are *still* trying to keep this thread going *but*
this is going to be my last post to it.
-See inline comments
"Rico" <ra*****@yahoo. com> wrote in message
news:pa******** *************** *****@yahoo.com ... On Sat, 11 Jun 2005 10:34:23 +0100, Mark Broadbent wrote: Really not sure what you are trying to say?
:)
That you are funny?
No.
You'll also note that I said "referencin g another instance you
are effectively making a copy" in this string scenario. What I mean by
'effectively' is that even *if* s1 did point to s2 at that time of
assignment, the exact moment that a change is made to either s1 or s2
they
would point to different instances due to the immutable rule (as my
simple
example shows).
The mention of "s2 = s1;"
'effectively' making a copy would lead one to think that the subsequent
's1 = "two" ; '
makes the initial object pointed to by s1 eligible for garbage collection,
whereas I should think that it is not because it is being pointed to by
s2.
Yes s2 does point to this instance, examining the machine code or IL shows
this. No, my previous posts were adequate and explanatory.
Also the term "effective" is completely fine in this context. "effective" !=
"actual".
to put it simply, the value that is referenced by a string variable is
protected from a change from another.
I think it's just more confusing to bring up 'effective copies' to
explain that. String is immutable. The content of the object it references
cannot be changed. Period.
I've already explained the immutable concept.
Also your description "object it references cannot be changed" is incorrect.
The referenced location is not safe from changes by pointers.
My description *is* correct "to put it simply, the value that is referenced
by a string variable is protected from a change from another."
What's up with the new school of thought of some need for protection from
"another" ? heh.
??? Sergei's example was incorrect for this scenario, which he readily
admits.
Rico. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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