If I have a parameter that has an Object type (as opposed to something like
a string), can I make that parameter a CONST?
Right now, if you pass an object into a sub/function, that sub/function can
modify the object no matter how it's defined (ByVal or ByRef).
In some cases, I want to make sure that you cannot modify the object. Is
there a way to do that in VS2003 or the up comming VS2005?
Thanks,
Brien King
20  5039 
On 2005-09-17, Brien King <sp********@arc aderestoration. com> wrote: If I have a parameter that has an Object type (as opposed to something like
a string), can I make that parameter a CONST?
That's kinda weirdly phrased, a string IS an Object, but the answer is
no.
Right now, if you pass an object into a sub/function, that sub/function can
modify the object no matter how it's defined (ByVal or ByRef).
In some cases, I want to make sure that you cannot modify the object. Is
there a way to do that in VS2003 or the up comming VS2005?
Nope. This seems to be one of those things that the CLR and .Net
language designers looked at and decided they just didn't want.
just pass a class or structure as the parameter and define a property as
readonly
now you can read the parameter but you can`t change it
Private Class constVal
ReadOnly Property example()
Get
Return "this is a constant value"
End Get
End Property
End Class
Private Sub test(ByVal x As constVal)
MsgBox(x.exampl e)
End Sub
Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
System.EventArg s) Handles Button1.Click
Dim y As New constVal
test(y)
End Sub
regards
Michel Posseth
"Brien King" <sp********@arc aderestoration. com> wrote in message
news:er******** ******@TK2MSFTN GP10.phx.gbl... If I have a parameter that has an Object type (as opposed to something
like a string), can I make that parameter a CONST?
Right now, if you pass an object into a sub/function, that sub/function
can modify the object no matter how it's defined (ByVal or ByRef).
In some cases, I want to make sure that you cannot modify the object. Is
there a way to do that in VS2003 or the up comming VS2005?
Thanks,
Brien King
"Brien King" <sp********@arc aderestoration. com> wrote in message
news:er******** ******@TK2MSFTN GP10.phx.gbl... If I have a parameter that has an Object type ...can I make that parameter
a CONST?
In some cases, I want to make sure that you cannot modify the object. Is
there a way to do that in VS2003 or the up comming VS2005?
There is no way to do so, but there may be acceptable work-around. You can
for example create a shadow struct that has members for the values you want
to pass by value, and a method in your class to generate that struct. You
would then pass the struct, which is passed by value.
--
Jesse Liberty
Author of .NET books for O'Reilly http://www.LibertyAssociates.com
"Brien King" <sp********@arc aderestoration. com> schrieb: If I have a parameter that has an Object type (as opposed to something
like a string), can I make that parameter a CONST?
Right now, if you pass an object into a sub/function, that sub/function
can modify the object no matter how it's defined (ByVal or ByRef).
In some cases, I want to make sure that you cannot modify the object. Is
there a way to do that in VS2003 or the up comming VS2005?
No.
--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>
after rethinking ,,, i provided a workaround but it is absolutely useless
why the $##$$# would you do that if you could just as easily use a local (
in the same class as the method ) contstant value
maybe we should ask you what is your situation in wich you think this is
needed ???
as i said i would not pass a contstant value at all to a parameter , i would
make it a class construct parameter and call it with a read only property in
the method itself
regards
Michel Posseth [MCP]
"Brien King" <sp********@arc aderestoration. com> wrote in message
news:er******** ******@TK2MSFTN GP10.phx.gbl... If I have a parameter that has an Object type (as opposed to something
like a string), can I make that parameter a CONST?
Right now, if you pass an object into a sub/function, that sub/function
can modify the object no matter how it's defined (ByVal or ByRef).
In some cases, I want to make sure that you cannot modify the object. Is
there a way to do that in VS2003 or the up comming VS2005?
Thanks,
Brien King
On 2005-09-17, m.posseth <mi*****@nohaus ystems.nl> wrote: after rethinking ,,, i provided a workaround but it is absolutely useless
why the $##$$# would you do that if you could just as easily use a local (
in the same class as the method ) contstant value
maybe we should ask you what is your situation in wich you think this is
needed ???
as i said i would not pass a contstant value at all to a parameter , i would
make it a class construct parameter and call it with a read only property in
the method itself
You're missing the point. What the OP wants is to pass reference types
to a method and ensure that the method won't change the contents of the
passed object. It would look something like this...
Public Sub Foo(ByConst list As ArrayList)
Console.Writeli ne(list(0)) ' This is OK
list(0) = "Hello" ' This would be a compile error
Because the list parameter is declared const, the Foo method can't
change the contents. This is a very common construct in C++, but
isn't supported in the CLR or the Framework.
regards
Michel Posseth [MCP]
"Brien King" <sp********@arc aderestoration. com> wrote in message
news:er******** ******@TK2MSFTN GP10.phx.gbl... If I have a parameter that has an Object type (as opposed to something
like a string), can I make that parameter a CONST?
Right now, if you pass an object into a sub/function, that sub/function
can modify the object no matter how it's defined (ByVal or ByRef).
In some cases, I want to make sure that you cannot modify the object. Is
there a way to do that in VS2003 or the up comming VS2005?
Thanks,
Brien King
David, You're missing the point. What the OP wants is to pass reference types
to a method and ensure that the method won't change the contents of the
passed object.
And in my opinion very correct answered by you last week. http://groups.google.com/group/micro...66eac3c?hl=en&
:-)
Cor
On 2005-09-17, Cor Ligthert [MVP] <no************ @planet.nl> wrote: David,
You're missing the point. What the OP wants is to pass reference types
to a method and ensure that the method won't change the contents of the
passed object.
And in my opinion very correct answered by you last week.
http://groups.google.com/group/micro...66eac3c?hl=en&
:-)
Yes, the same questions do seem to pop up here quite often.
No i am not missing the point ,
i do understand that what he want is not possible in this way , however i
provided a workaround to acomplish something simular
however after rethinking my first solution i thought that there is a much
better way
If i rethink this in a OOP way it isn`t so difficult to acomplish at all
( define the needed business rules in some objects on demand ) ,,, however
it is still a workaround but it will do what he wants
well .... maybe i should have mentioned the impossibility in forehand , but
as i read the hole thread i base my answer on what is previously said
( sorry :-)
regards
and have a nice weekend
Michel Posseth
"david" <da***@woofix.l ocal.dom> wrote in message
news:sl******** **********@loca lhost.localdoma in... On 2005-09-17, m.posseth <mi*****@nohaus ystems.nl> wrote: after rethinking ,,, i provided a workaround but it is absolutely
useless
why the $##$$# would you do that if you could just as easily use a local
(
in the same class as the method ) contstant value
maybe we should ask you what is your situation in wich you think this is
needed ???
as i said i would not pass a contstant value at all to a parameter , i
would
make it a class construct parameter and call it with a read only property
in
the method itself
You're missing the point. What the OP wants is to pass reference types
to a method and ensure that the method won't change the contents of the
passed object. It would look something like this...
Public Sub Foo(ByConst list As ArrayList)
Console.Writeli ne(list(0)) ' This is OK
list(0) = "Hello" ' This would be a compile error
Because the list parameter is declared const, the Foo method can't
change the contents. This is a very common construct in C++, but
isn't supported in the CLR or the Framework.
regards
Michel Posseth [MCP]
"Brien King" <sp********@arc aderestoration. com> wrote in message
news:er******** ******@TK2MSFTN GP10.phx.gbl... If I have a parameter that has an Object type (as opposed to something
like a string), can I make that parameter a CONST?
Right now, if you pass an object into a sub/function, that sub/function
can modify the object no matter how it's defined (ByVal or ByRef).
In some cases, I want to make sure that you cannot modify the object.
Is
there a way to do that in VS2003 or the up comming VS2005?
Thanks,
Brien King
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