Static Class Constants (VB 2005)

[Michael D. Ober]

Is there any way to create a constant in a class that can be used both with
an instantiated object and without. For example:

dim ClassConst as string = myClass.Constan tString

dim myObj = new MyClass
ClassConst = myObj.ConstantS tring

Inside the class MyClass

Class MyClass

public const ConstantString = "Some Constant String"

End Class

In Beta 2, ConstantString was available in either of the above cases without
complaint. In the RTM version, I can't do both. I don't want to turn off
the warning as doing so may actually introduce another bug in my code later
because I didn't see the warning.

Thanks,
Mike.

[Marina]

If it's a constant, why not always reference it through the type name? What
do you gain by accessing it through an instance?

"Michael D. Ober" <obermd.@.alum. mit.edu.nospam> wrote in message
news:uj******** *****@TK2MSFTNG P14.phx.gbl...

Is there any way to create a constant in a class that can be used both
with
an instantiated object and without. For example:

dim ClassConst as string = myClass.Constan tString

dim myObj = new MyClass
ClassConst = myObj.ConstantS tring

Inside the class MyClass

Class MyClass

public const ConstantString = "Some Constant String"

End Class

In Beta 2, ConstantString was available in either of the above cases
without
complaint. In the RTM version, I can't do both. I don't want to turn off
the warning as doing so may actually introduce another bug in my code
later
because I didn't see the warning.

Thanks,
Mike.

[Herfried K. Wagner [MVP]]

Marina,

"Marina" <so*****@nospam .com> schrieb:

If it's a constant, why not always reference it through the type name?
What do you gain by accessing it through an instance?

What do you loose by accessing it through an instance?

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[m.posseth]

Michael
i use the release version of Visual studio 2005 ( professional edition )

Public Class Form1
Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
System.EventArg s) Handles Button1.Click

Dim ClassConst As String = XMyClass.Consta ntString

MsgBox(ClassCon st)

Dim myObj = New XMyClass

ClassConst = myObj.ConstantS tring

MsgBox(ClassCon st)

End Sub

End Class

Class XMyClass

Public Const ConstantString = "Some Constant String"

End Class

this works without anny problems on my dev computer ( no warnings )

regards

Michel Posseth [MCP]
"Michael D. Ober" <obermd.@.alum. mit.edu.nospam> wrote in message
news:uj******** *****@TK2MSFTNG P14.phx.gbl...

Is there any way to create a constant in a class that can be used both
with
an instantiated object and without. For example:

dim ClassConst as string = myClass.Constan tString

dim myObj = new MyClass
ClassConst = myObj.ConstantS tring

Inside the class MyClass

Class MyClass

public const ConstantString = "Some Constant String"

End Class

In Beta 2, ConstantString was available in either of the above cases
without
complaint. In the RTM version, I can't do both. I don't want to turn off
the warning as doing so may actually introduce another bug in my code
later
because I didn't see the warning.

Thanks,
Mike.

[Michael D. Ober]

Code readability.

Mike.

"Marina" <so*****@nospam .com> wrote in message
news:OE******** *****@tk2msftng p13.phx.gbl...

If it's a constant, why not always reference it through the type name? What do you gain by accessing it through an instance?

"Michael D. Ober" <obermd.@.alum. mit.edu.nospam> wrote in message
news:uj******** *****@TK2MSFTNG P14.phx.gbl...

Is there any way to create a constant in a class that can be used both
with
an instantiated object and without. For example:

dim ClassConst as string = myClass.Constan tString

dim myObj = new MyClass
ClassConst = myObj.ConstantS tring

Inside the class MyClass

Class MyClass

public const ConstantString = "Some Constant String"

End Class

In Beta 2, ConstantString was available in either of the above cases
without
complaint. In the RTM version, I can't do both. I don't want to turn off the warning as doing so may actually introduce another bug in my code
later
because I didn't see the warning.

Thanks,
Mike.

[Michael D. Ober]

There are times when accessing through an instance makes more sense - it
ensures I'm working with the correct object/class type. Other times,
accessing through the class type make more sense - when trying to verify
class type of an unknown string representation of the object. In the latter
case, class type verification can then be done without the overhead of
creating an object that then gets immediately thrown away.

Mike Ober.

"Herfried K. Wagner [MVP]" <hi************ ***@gmx.at> wrote in message
news:OA******** ******@TK2MSFTN GP15.phx.gbl...

Marina,

"Marina" <so*****@nospam .com> schrieb:

If it's a constant, why not always reference it through the type name?
What do you gain by accessing it through an instance?

What do you loose by accessing it through an instance?

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Marina]

Apparently you lose the ability to compile without getting a warner. You
also lose code clarity, as now it is not obvious this is a constant. It
could just be an instance property of the class, and it's not at all obvious
that it is not. Where as seeing the type name in front, you see that this
something that exists only once for the class.

The point is, if you don't gain anything by doing it, and you lose
readability, then why do it?

"Herfried K. Wagner [MVP]" <hi************ ***@gmx.at> wrote in message
news:OA******** ******@TK2MSFTN GP15.phx.gbl...

Marina,

"Marina" <so*****@nospam .com> schrieb:

If it's a constant, why not always reference it through the type name?
What do you gain by accessing it through an instance?

What do you loose by accessing it through an instance?

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Michael D. Ober]

Regardless of Option Explicit and Option Strict settings on a brand new form
with a single button, I get the error "Access of shared member, constant
member, enum member or nested type through an instance; qualifying
expression will not be evaluated." on your code sample. VS 2005 Standard
RTM.

Mike.

"m.posseth" <mi*****@nohaus ystems.nl> wrote in message
news:ev******** ******@TK2MSFTN GP14.phx.gbl...

Michael
i use the release version of Visual studio 2005 ( professional edition )

Public Class Form1
Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
System.EventArg s) Handles Button1.Click

Dim ClassConst As String = XMyClass.Consta ntString

MsgBox(ClassCon st)

Dim myObj = New XMyClass

''''''''''''' Error is on this line ClassConst = myObj.ConstantS tring

MsgBox(ClassCon st)

End Sub

End Class

Class XMyClass

Public Const ConstantString = "Some Constant String"

End Class

this works without anny problems on my dev computer ( no warnings )

regards

Michel Posseth [MCP]
"Michael D. Ober" <obermd.@.alum. mit.edu.nospam> wrote in message
news:uj******** *****@TK2MSFTNG P14.phx.gbl...

Is there any way to create a constant in a class that can be used both
with
an instantiated object and without. For example:

dim ClassConst as string = myClass.Constan tString

dim myObj = new MyClass
ClassConst = myObj.ConstantS tring

Inside the class MyClass

Class MyClass

public const ConstantString = "Some Constant String"

End Class

In Beta 2, ConstantString was available in either of the above cases
without
complaint. In the RTM version, I can't do both. I don't want to turn off the warning as doing so may actually introduce another bug in my code
later
because I didn't see the warning.

Thanks,
Mike.

[Marina]

If this is about a constant, how does that help ensure you are working with
the right class? There is no inheritance issue here.

"Michael D. Ober" <obermd.@.alum. mit.edu.nospam> wrote in message
news:OI******** ******@TK2MSFTN GP10.phx.gbl...

There are times when accessing through an instance makes more sense - it
ensures I'm working with the correct object/class type. Other times,
accessing through the class type make more sense - when trying to verify
class type of an unknown string representation of the object. In the
latter
case, class type verification can then be done without the overhead of
creating an object that then gets immediately thrown away.

Mike Ober.

"Herfried K. Wagner [MVP]" <hi************ ***@gmx.at> wrote in message
news:OA******** ******@TK2MSFTN GP15.phx.gbl...

Marina,

"Marina" <so*****@nospam .com> schrieb:

> If it's a constant, why not always reference it through the type name?
> What do you gain by accessing it through an instance?

What do you loose by accessing it through an instance?

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Herfried K. Wagner [MVP]]

"Marina" <so*****@nospam .com> schrieb:

If this is about a constant, how does that help ensure you are working
with the right class? There is no inheritance issue here.

That's true, but especially when dealing with public constants it seems
completely irrelevant to me whether or not the member belongs to an instance
or the class itself. I agree that it doesn't make much sense to obtain a
reference to an object using complicated code only to access one of the
public constants of the class.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>