Hi all,
I am wondering why string's are not true objects?.... Let me explain...
If i write the code
Dim x1 as String = "veg"
Dim x2 as String = "veg"
If x1 = x2 then
' i expect this code to be executed
End If
If x1 is x2 then
' i do not expect this code to be executed
End If
However the second lot of code is executed!
Is this correct behavior??? if so is it true then that strings are not true
objects?
Any thoughts would be appreciated!
Rigga.
42  1634 
* "Rigga" <s@v.c> scripsit: I am wondering why string's are not true objects?.... Let me explain...
If i write the code
Dim x1 as String = "veg"
Dim x2 as String = "veg"
If x1 = x2 then
' i expect this code to be executed
End If
If x1 is x2 then
' i do not expect this code to be executed
End If
However the second lot of code is executed!
Is this correct behavior??? if so is it true then that strings are not true
objects?
Why not? Both string objects are pointing to the same "constant".
--
Herfried K. Wagner [MVP]
<URL:http://dotnet.mvps.org/>
I believe the String is a true object, but it Overloads the '=' Operator.
so when you write the code x1=x2 the and x1 and x2 are both strings, it will
actually compile the same as x1 is x2. If your using C#, you can overload
operators for your own classes, and make them behave the same way.
Lance
"Rigga" <s@v.c> wrote in message
news:40******** *************@p tn-nntp-reader04.plus.n et...
Hi all,
I am wondering why string's are not true objects?.... Let me explain...
If i write the code
Dim x1 as String = "veg"
Dim x2 as String = "veg"
If x1 = x2 then
' i expect this code to be executed
End If
If x1 is x2 then
' i do not expect this code to be executed
End If
However the second lot of code is executed!
Is this correct behavior??? if so is it true then that strings are not true
objects?
Any thoughts would be appreciated!
Rigga.
David Williams <Da***********@ discussions.mic rosoft.com> wrote: Remember that strings are ValueTypes, not ReferenceTypes.
No they're not. They're reference types. There are any numbers of ways
to verify that, but Type.IsValueTyp e is probably the easiest.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
* "=?Utf-8?B?RGF2aWQgV2l sbGlhbXM=?=" <Da***********@ discussions.mic rosoft.com> scripsit: Remember that strings are ValueTypes, not ReferenceTypes.
No! Strings are not value types, they don't inherit from
'System.ValueTy pe':
\\\
Dim s As String = "Hello World"
MsgBox(TypeOf s Is ValueType)
///
--
Herfried K. Wagner [MVP]
<URL:http://dotnet.mvps.org/>
But let's not forget that they are immutable.... When you change the value
of a string object, the object is destroyed and a brand new one is created.
--
HTH,
-- Tom Spink, Über Geek
Woe be the day VBC.EXE says, "OrElse what?"
Please respond to the newsgroup,
so all can benefit
"Herfried K. Wagner [MVP]" <hi************ ***@gmx.at> wrote in message
news:2l******** ****@uni-berlin.de... * "=?Utf-8?B?RGF2aWQgV2l sbGlhbXM=?="
<Da***********@ discussions.mic rosoft.com> scripsit: Remember that strings are ValueTypes, not ReferenceTypes.
No! Strings are not value types, they don't inherit from
'System.ValueTy pe':
\\\
Dim s As String = "Hello World"
MsgBox(TypeOf s Is ValueType)
///
--
Herfried K. Wagner [MVP]
<URL:http://dotnet.mvps.org/>
Thanks all for your replies but I'm still confused.
So coding "veg" anywhere will only ever create one object?
and assigning that object to the reference variable as
x1 as string = "veg"
points to the same object as
x2 as string = "veg"
"veg" being the object?
actually, it has always been kind of strange hat you do not have to code
x1 as New String to instantiate the object.
So we are saying that string does not behave in the same way as other
objects?
Anyway, now that I know this I'll have to code around it.. thanks all..
Rigga.
"Rigga" <s@v.c> wrote in message
news:40******** *************@p tn-nntp-reader04.plus.n et... Hi all,
I am wondering why string's are not true objects?.... Let me explain...
If i write the code
Dim x1 as String = "veg"
Dim x2 as String = "veg"
If x1 = x2 then
' i expect this code to be executed
End If
If x1 is x2 then
' i do not expect this code to be executed
End If
However the second lot of code is executed!
Is this correct behavior??? if so is it true then that strings are not
true objects?
Any thoughts would be appreciated!
Rigga.
Hi Tom,
From you I had expected more, the question is (see it yourself) ..... And
now everybody telling that a string object is a reference type or something
like that.
:-)
Cor
Tom Spink <thomasdotspink atsp@mntlworldd otcom> wrote: But let's not forget that they are immutable.... When you change the value
of a string object, the object is destroyed and a brand new one is created.
Um, no. You *can't* "change the value" of a string object. You can
change the value of a variable so that it's a reference to a different
string, but that doesn't necessarily destroy the old string or create a
new one.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
Rigga <s@v.c> wrote: Thanks all for your replies but I'm still confused.
So coding "veg" anywhere will only ever create one object?
and assigning that object to the reference variable as
x1 as string = "veg"
points to the same object as
x2 as string = "veg"
"veg" being the object?
actually, it has always been kind of strange hat you do not have to code
x1 as New String to instantiate the object.
So we are saying that string does not behave in the same way as other
objects?
Anyway, now that I know this I'll have to code around it.. thanks all..
String behaves like other objects for the most part, but string
literals are interned automatically, so that within a single AppDomain,
all references to the same string literal are references to the same
actual string.
One *really* weird bit about string is that if you create a new string
using the char[] constructor, but give it an empty array, it doesn't
actually create a new string at all - it just returns String.Empty.
Very odd indeed.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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Hi all,
I am wondering why string's are not true objects?.... Let me explain...
If i write the code
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Dim x2 as String = "veg"
If x1 = x2 then
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