Multi Inherence

[Bernard Bourée]

Is there a way to overpass the impossibility of VN.NET to accept the multi
heritage, that is to allow a class to inherit from TWO mother classes ?

--
Bernard Bourée
be*****@bouree. net

[Bernard Bourée]

Well if I try to make it simple

I have one class named FLUID which contains various properties like
Pressure
Temp
FlowRate

An other class named DROP which contains properties like
Diameter
Temp
Pressure

And a last one called SECTION which should contains the properties of FLUID,
DROP plus some others.
So the solution I have now is to make a copy of the FLUID's properties
inside SECTION

But If I have to change the properties of FLUID I have to remind to do it in
both places.

Thank for your help

--
Bernard Bourée
be*****@bouree. net
"Larry Serflaten" <se*******@usin ternet.com> a écrit dans le message de
news:%2******** ********@tk2msf tngp13.phx.gbl. ..

"Bernard Bourée" <be*****@bouree .net> wrote

Is there a way to overpass the impossibility of VN.NET to accept the multi heritage, that is to allow a class to inherit from TWO mother classes ?
If there was a often used need for multiple inheritance, then MS would

have probably found a way to include it. Evidently they decided there wasn't
an absolute need that would be common enough for the functionality.

Perhaps if you describe what you want to do, someone can explain how
to do that within the confines of the language you are using....

LFS

[Jay B. Harlow [MVP - Outlook]]

Bernard,
In addition to the other comments, you could use one or more Interfaces:

Something like:
Public Interface IFluid
Property Pressure() As Integer
Property Temp() As Integer
Property FlowRate() As Integer
End Interface

Public Class Fluid
Implements IFluid

Private m_flowRate As Integer
Private m_pressure As Integer
Private m_temp As Integer

Public Property FlowRate() As Integer Implements IFluid.FlowRate
Get
Return m_flowRate
End Get
Set(ByVal value As Integer)
m_flowRate = value
End Set
End Property

Public Property Pressure() As Integer Implements IFluid.Pressure
Get
Return m_pressure
End Get
Set(ByVal value As Integer)
m_pressure = value
End Set
End Property

Public Property Temp() As Integer Implements IFluid.Temp
Get
Return m_temp
End Get
Set(ByVal value As Integer)
m_temp = value
End Set
End Property

End Class

Public Interface IDrop
Property Diameter() As Integer
Property Temp() As Integer
Property Pressure() As Integer
End Interface

Public Class Drop
Implements IDrop

Private m_diameter As Integer
Private m_pressure As Integer
Private m_temp As Integer

Public Property Diameter() As Integer Implements IDrop.Diameter
Get
Return m_diameter
End Get
Set(ByVal value As Integer)
m_diameter = value
End Set
End Property

Public Property Pressure() As Integer Implements IDrop.Pressure
Get
Return m_pressure
End Get
Set(ByVal value As Integer)
m_pressure = value
End Set
End Property

Public Property Temp() As Integer Implements IDrop.Temp
Get
Return m_temp
End Get
Set(ByVal value As Integer)
m_temp = value
End Set
End Property

End Class

Public Interface ISection
Inherits IFluid
Inherits IDrop
End Interface

Public Class Section
Implements ISection

Private m_flowRate As Integer
Private m_pressure As Integer
Private m_temp As Integer
Private m_diameter As Integer

Public Property FlowRate() As Integer Implements IFluid.FlowRate
Get
Return m_flowRate
End Get
Set(ByVal value As Integer)
m_flowRate = value
End Set
End Property

Public Property Pressure() As Integer Implements IFluid.Pressure ,
IDrop.Pressure
Get
Return m_pressure
End Get
Set(ByVal value As Integer)
m_pressure = value
End Set
End Property

Public Property Temp() As Integer Implements IFluid.Temp, IDrop.Temp
Get
Return m_temp
End Get
Set(ByVal value As Integer)
m_temp = value
End Set
End Property

Public Property Diameter() As Integer Implements IDrop.Diameter
Get
Return m_diameter
End Get
Set(ByVal value As Integer)
m_diameter = value
End Set
End Property

End Class

Then rather then define your parameters as the class, you would define them
as the Interface.

For Example:

Public Shared Sub ProcessFluid(By Val aFluid As IFluid)
Debug.WriteLine (CObj(aFluid).G etType().Name)
Debug.Indent()
Debug.WriteLine (aFluid.Pressur e, "Fluid.Pressure ")
Debug.WriteLine (aFluid.Temp, "Fluid.Temp ")
Debug.WriteLine (aFluid.FlowRat e, "Fluid.FlowRate ")
Debug.Unindent( )
End Sub

Public Shared Sub ProcessDrop(ByV al aDrop As IDrop)
Debug.WriteLine (CObj(aFluid).G etType().Name)
Debug.Indent()
Debug.WriteLine (aDrop.Diameter , "Drop.Diameter" )
Debug.WriteLine (aDrop.Temp, "Drop.Diameter" )
Debug.WriteLine (aDrop.Pressure , "Drop.Pressure" )
Debug.Unindent( )
End Sub
Public Shared Sub Main()
Dim aFluid As New Fluid
Dim aDrop As New Drop
Dim aSection As New Section
ProcessFluid(aF luid)
ProcessFluid(aS ection)

ProcessDrop(aDr op)
ProcessDrop(aSe ction)
End Sub

Note you don't need to use three actual interface, you can get by with only
defining Fluid or Drop in terms on an interface, then Section could inherit
from the other & implement the interface. The key is to use the Interface
instead of the class when you want to accept a Section in addition to the
class... Section could also implement ISection by using delegation to actual
Fluid & Drop objects...

Hope this helps
Jay
"Bernard Bourée" <be*****@bouree .net> wrote in message
news:ek******** ******@TK2MSFTN GP15.phx.gbl...

Well if I try to make it simple

I have one class named FLUID which contains various properties like
Pressure
Temp
FlowRate

An other class named DROP which contains properties like
Diameter
Temp
Pressure

And a last one called SECTION which should contains the properties of
FLUID,
DROP plus some others.
So the solution I have now is to make a copy of the FLUID's properties
inside SECTION

But If I have to change the properties of FLUID I have to remind to do it
in
both places.

Thank for your help

--
Bernard Bourée
be*****@bouree. net
"Larry Serflaten" <se*******@usin ternet.com> a écrit dans le message de
news:%2******** ********@tk2msf tngp13.phx.gbl. ..

"Bernard Bourée" <be*****@bouree .net> wrote

> Is there a way to overpass the impossibility of VN.NET to accept the multi > heritage, that is to allow a class to inherit from TWO mother classes ?

If there was a often used need for multiple inheritance, then MS would

have

probably found a way to include it. Evidently they decided there wasn't
an absolute need that would be common enough for the functionality.

Perhaps if you describe what you want to do, someone can explain how
to do that within the confines of the language you are using....

LFS

[Mike Labosh]

> C++ can do multiple inheritance, Managed C++ cannot.

Interesting --- the single inheritance thing is a "feature" of the CLR then?
--
Peace & happy computing,

Mike Labosh, MCSD
"I have no choice but to believe in free will."

[Jeff Louie]

Mike... True. But only if you mean implementation inheritance. The CLR
supports single inheritance of implementation and multiple inheritance
of
interfaces. In C#:

http://www.geocities.com/jeff_louie/OOP/oop9.htm
http://www.geocities.com/jeff_louie/OOP/oop16.htm

Regards,
Jeff

Interesting --- the single inheritance thing is a "feature" of the CLR

then?<
*** Sent via Developersdex http://www.developersdex.com ***
Don't just participate in USENET...get rewarded for it!

[Dennis]

Just curious but if you can inheirit two interfaces and both have a property
or method that has the same name, how can you tell which one to use?

"Mike McIntyre" wrote:

Bernard,
While Microsoft's .NET programming languages do not provide
multiple-inheritence they do provide ways to implement multiple-inheritance
like behavior.

There are other .NET programming languages that do support
multiple-inheritance:

Haskell.NET (HUGS98) is Haskell as a .NET programming language that allows
multiple-inheritance.

Eifel for .NET is another .NET programming language that allows
multiple-inhieritance:

http://msdn.microsoft.com/library/de...pdc_eiffel.asp
--
Mike

Mike McIntyre
Visual Basic MVP
www.getdotnetcode.com
"Bernard Bourée" <be*****@bouree .net> wrote in message
news:eF******** *****@TK2MSFTNG P11.phx.gbl...

Is there a way to overpass the impossibility of VN.NET to accept the multi
heritage, that is to allow a class to inherit from TWO mother classes ?

--
Bernard Bourée
be*****@bouree. net

[Larry Serflaten]

"Bernard Bourée" <be*****@bouree .net> wrote

Well if I try to make it simple

I have one class named FLUID which contains various properties like
Pressure
Temp
FlowRate

An other class named DROP which contains properties like
Diameter
Temp
Pressure

And a last one called SECTION which should contains the properties of FLUID,
DROP plus some others.
So the solution I have now is to make a copy of the FLUID's properties
inside SECTION

But If I have to change the properties of FLUID I have to remind to do it in
both places.

What you list does not appear to be inheritance, but rather polymorphism.
Inheritance is involved when class Drop "is a" class Fluid, which may or
may not be inherited, that part wasn't clear (cute pun, eh?). But then you
have a class Section that has the properties of Fluid, and the properties of
Drop, and the properties of some others. That involves polymorphism.

If that is what you want then you need to use interfaces, like Jay suggests.

HTH
LFS

[Larry Serflaten]

"Dennis" <De****@discuss ions.microsoft. com> wrote

Just curious but if you can inheirit two interfaces and both have a property
or method that has the same name, how can you tell which one to use?

How can _who_ tell which one to use? The user or the class developer?

When you implement a member of an interface, the member is marked:

Private Sub SomeMethod() Implements MyInterface.MyM ethod

Because both the interface and method are named, the CLR won't get confused....

LFS

[Mike Labosh]

consider this aircode:

Public Interface IFoo
Sub ThisMethod() 'same signature
End Interface

Public Interface IFee
Sub ThisMethod() 'same signature
End Interface

Public Class Fum Implements IFoo Implements IFee
Public Sub ThisMethod() Implements IFoo.ThisMethod
'stuff
End Sub
Public Sub ThisMethod() Implements IFee.ThisMethod
'other stuff
End Sub
End Class

I didn't try to compile it (it's late) but each method implementation is
clearly marked as to whose interface it's implementing.
--
Peace & happy computing,

Mike Labosh, MCSD
"I have no choice but to believe in free will."

[Jay B. Harlow [MVP - Outlook]]

Dennis,
My earlier sample shows one way of implementing two interfaces with the same
method.

Another way is to explicitly name the methods in the implementing class,
when I do this, I make the methods private:

Something like:

Public Class Section
Implements ISection

Private m_flowRate As Integer
Private m_pressure As Integer
Private m_temp As Integer
Private m_diameter As Integer

Public Property FlowRate() As Integer Implements IFluid.FlowRate
Get
Return m_flowRate
End Get
Set(ByVal value As Integer)
m_flowRate = value
End Set
End Property

Public Property Pressure() As Integer Implements IFluid.Pressure ,
IDrop.Pressure
Get
Return m_pressure
End Get
Set(ByVal value As Integer)
m_pressure = value
End Set
End Property

Public Property Temp() As Integer
Get
Return m_temp
End Get
Set(ByVal value As Integer)
m_temp = value
End Set
End Property

Private Property IFluid_Temp() As Integer Implements IDrop.Temp
Get
' do something unique for IFluid
Return m_temp
End Get
Set(ByVal value As Integer)
' do something unique for IFluid
m_temp = value
End Set
End Property

Private Property IDrop_Temp() As Integer IDrop.Temp
Get
' do something unique for IDrop
Return m_temp
End Get
Set(ByVal value As Integer)
' do something unique for IDrop
m_temp = value
End Set
End Property

Public Property Diameter() As Integer Implements IDrop.Diameter
Get
Return m_diameter
End Get
Set(ByVal value As Integer)
m_diameter = value
End Set
End Property

End Class
"Dennis" <De****@discuss ions.microsoft. com> wrote in message
news:F0******** *************** ***********@mic rosoft.com...

Just curious but if you can inheirit two interfaces and both have a
property
or method that has the same name, how can you tell which one to use?

"Mike McIntyre" wrote:

Bernard,
While Microsoft's .NET programming languages do not provide
multiple-inheritence they do provide ways to implement
multiple-inheritance
like behavior.

There are other .NET programming languages that do support
multiple-inheritance:

Haskell.NET (HUGS98) is Haskell as a .NET programming language that
allows
multiple-inheritance.

Eifel for .NET is another .NET programming language that allows
multiple-inhieritance:

http://msdn.microsoft.com/library/de...pdc_eiffel.asp
--
Mike

Mike McIntyre
Visual Basic MVP
www.getdotnetcode.com
"Bernard Bourée" <be*****@bouree .net> wrote in message
news:eF******** *****@TK2MSFTNG P11.phx.gbl...

> Is there a way to overpass the impossibility of VN.NET to accept the
> multi
> heritage, that is to allow a class to inherit from TWO mother classes ?
>
> --
> Bernard Bourée
> be*****@bouree. net
>
>

[Bernard Bourée]

Jay

Thank you so much for your help !!!

--
Bernard Bourée
be*****@bouree. net
"Jay B. Harlow [MVP - Outlook]" <Ja************ @msn.com> a écrit dans le
message de news:Oh******** ******@tk2msftn gp13.phx.gbl...

Bernard,
In addition to the other comments, you could use one or more Interfaces:

Something like:
Public Interface IFluid
Property Pressure() As Integer
Property Temp() As Integer
Property FlowRate() As Integer
End Interface

Public Class Fluid
Implements IFluid

Private m_flowRate As Integer
Private m_pressure As Integer
Private m_temp As Integer

Public Property FlowRate() As Integer Implements IFluid.FlowRate
Get
Return m_flowRate
End Get
Set(ByVal value As Integer)
m_flowRate = value
End Set
End Property

Public Property Pressure() As Integer Implements IFluid.Pressure
Get
Return m_pressure
End Get
Set(ByVal value As Integer)
m_pressure = value
End Set
End Property

Public Property Temp() As Integer Implements IFluid.Temp
Get
Return m_temp
End Get
Set(ByVal value As Integer)
m_temp = value
End Set
End Property

End Class

Public Interface IDrop
Property Diameter() As Integer
Property Temp() As Integer
Property Pressure() As Integer
End Interface

Public Class Drop
Implements IDrop

Private m_diameter As Integer
Private m_pressure As Integer
Private m_temp As Integer

Public Property Diameter() As Integer Implements IDrop.Diameter
Get
Return m_diameter
End Get
Set(ByVal value As Integer)
m_diameter = value
End Set
End Property

Public Property Pressure() As Integer Implements IDrop.Pressure
Get
Return m_pressure
End Get
Set(ByVal value As Integer)
m_pressure = value
End Set
End Property

Public Property Temp() As Integer Implements IDrop.Temp
Get
Return m_temp
End Get
Set(ByVal value As Integer)
m_temp = value
End Set
End Property

End Class

Public Interface ISection
Inherits IFluid
Inherits IDrop
End Interface

Public Class Section
Implements ISection

Private m_flowRate As Integer
Private m_pressure As Integer
Private m_temp As Integer
Private m_diameter As Integer

Public Property FlowRate() As Integer Implements IFluid.FlowRate
Get
Return m_flowRate
End Get
Set(ByVal value As Integer)
m_flowRate = value
End Set
End Property

Public Property Pressure() As Integer Implements IFluid.Pressure ,
IDrop.Pressure
Get
Return m_pressure
End Get
Set(ByVal value As Integer)
m_pressure = value
End Set
End Property

Public Property Temp() As Integer Implements IFluid.Temp, IDrop.Temp Get
Return m_temp
End Get
Set(ByVal value As Integer)
m_temp = value
End Set
End Property

Public Property Diameter() As Integer Implements IDrop.Diameter
Get
Return m_diameter
End Get
Set(ByVal value As Integer)
m_diameter = value
End Set
End Property

End Class

Then rather then define your parameters as the class, you would define them as the Interface.

For Example:

Public Shared Sub ProcessFluid(By Val aFluid As IFluid)
Debug.WriteLine (CObj(aFluid).G etType().Name)
Debug.Indent()
Debug.WriteLine (aFluid.Pressur e, "Fluid.Pressure ")
Debug.WriteLine (aFluid.Temp, "Fluid.Temp ")
Debug.WriteLine (aFluid.FlowRat e, "Fluid.FlowRate ")
Debug.Unindent( )
End Sub

Public Shared Sub ProcessDrop(ByV al aDrop As IDrop)
Debug.WriteLine (CObj(aFluid).G etType().Name)
Debug.Indent()
Debug.WriteLine (aDrop.Diameter , "Drop.Diameter" )
Debug.WriteLine (aDrop.Temp, "Drop.Diameter" )
Debug.WriteLine (aDrop.Pressure , "Drop.Pressure" )
Debug.Unindent( )
End Sub
Public Shared Sub Main()
Dim aFluid As New Fluid
Dim aDrop As New Drop
Dim aSection As New Section
ProcessFluid(aF luid)
ProcessFluid(aS ection)

ProcessDrop(aDr op)
ProcessDrop(aSe ction)
End Sub

Note you don't need to use three actual interface, you can get by with only defining Fluid or Drop in terms on an interface, then Section could inherit from the other & implement the interface. The key is to use the Interface
instead of the class when you want to accept a Section in addition to the
class... Section could also implement ISection by using delegation to actual Fluid & Drop objects...

Hope this helps
Jay
"Bernard Bourée" <be*****@bouree .net> wrote in message
news:ek******** ******@TK2MSFTN GP15.phx.gbl...

Well if I try to make it simple

I have one class named FLUID which contains various properties like
Pressure
Temp
FlowRate

An other class named DROP which contains properties like
Diameter
Temp
Pressure

And a last one called SECTION which should contains the properties of
FLUID,
DROP plus some others.
So the solution I have now is to make a copy of the FLUID's properties
inside SECTION

But If I have to change the properties of FLUID I have to remind to do it in
both places.

Thank for your help

--
Bernard Bourée
be*****@bouree. net
"Larry Serflaten" <se*******@usin ternet.com> a écrit dans le message de
news:%2******** ********@tk2msf tngp13.phx.gbl. ..

"Bernard Bourée" <be*****@bouree .net> wrote
> Is there a way to overpass the impossibility of VN.NET to accept the

multi

> heritage, that is to allow a class to inherit from TWO mother classes ?
If there was a often used need for multiple inheritance, then MS would

have

probably found a way to include it. Evidently they decided there wasn't an absolute need that would be common enough for the functionality.

Perhaps if you describe what you want to do, someone can explain how
to do that within the confines of the language you are using....

LFS