Inheritance

**Vijay** · Apr 3 '06, 10:45 PM

Re: Inheritance

yes the reason to override are more applicable to methods, properties yes..
if you want to additional functionality to than what is available in the
base class.. I also strongly recommend that any public variables you declare
and intended to use a property or have thought it must be overridden, given
them as property definitions its much cleaner that way

VJ

"tshad" <tscheiderich@f tsolutions.com> wrote in message
news:u$wTCq2VGH A.5808@TK2MSFTN GP12.phx.gbl...[color=blue]
>I am playing with Inheritance and want to make sure I understand it.
>
> I have the following Classes:
> *************** *************** *************
> Public Class AuthHeader:Inhe rits SoapHeader
> Public AuthHeaderName As String
> Public SessionKey As String = "Default"
> End Class
>
> Public Class ServiceTicket:I nherits AuthHeader
> Public IsAuthenticated As Boolean
> Public SessionKey As String = "Default from ServiceTicket"
> Public Expiration As DateTime
> End Class
>
> Public Class TempClass1:Inhe rits ServiceTicket
> Public TomsClass1Name As String
> End Class
> *************** *************** ***********
>
> I assume that inheritance depends on the order of definition.
>
> Here SessionKey is being defined in 2 classes. For TempClass1 and
> ServiceTicket, Session would be "Default from ServiceTicket" since it
> would have been defined second. So if I create TempClass1, it would work
> something like, SessionKey would first be "Default" but then ServiceTicket
> would re-define it, since it inherited it (and is higher up the chain) and
> change it to "Default from ServiceTicket".
>
> In this case, if I had:
>
> Dim objTempClass1 As new TempClass1
> Dim objServiceTicke t As new ServiceTicket
> Dim objAuthHeader As new AuthHeader
>
> objTempClass1.S essionKey = "Default from ServiceTicket" '
> Inherited from ServiceKey
> objServiceKey.S essionKey = "Default from ServiceTicket"
> objAuthHeader.S essionKey = "Default"
>
> But if I took out the Sessionkey from the ServiceKey class that it would
> be:
>
> objTempClass1.S essionKey = "Default" ' Inherited
> from AuthHeader
> objServiceKey.S essionKey = "Default" ' Inherited
> from AuthHeader
> objAuthHeader.S essionKey = "Default"
>
> Also, I originally got this from a sample program that didn't set the
> defaults, but had it defined as:
> *************** *************** *************
> Public Class AuthHeader:Inhe rits SoapHeader
> Public AuthHeaderName As String
> Public SessionKey As String
> End Class
>
> Public Class ServiceTicket:I nherits AuthHeader
> Public IsAuthenticated As Boolean
> Public SessionKey As String
> Public Expiration As DateTime
> End Class
>
> Public Class TempClass1:Inhe rits ServiceTicket
> Public TomsClass1Name As String
> End Class
> *************** *************** ***********
>
> Is there any good reason to defining SessionKey again ServiceTicket?
>
> I assume since it always would inherit from AuthHeader, it would always
> get SessionKey from the inheritance. If it wanted to set SessionKey in
> ServiceTicket, it could just set it by:
>
> SessionKey = "Default"
>
> without needing to redefine it.
>
> Is this correct?
>
> Thanks,
>
> Tom
>
>[/color]

**tshad** · Apr 4 '06, 12:15 AM

Re: Inheritance

"Vijay" <vijay@msdiscus sions.com> wrote in message
news:e4p7432VGH A.4416@TK2MSFTN GP15.phx.gbl...[color=blue]
> yes the reason to override are more applicable to methods, properties
> yes.. if you want to additional functionality to than what is available in
> the base class.. I also strongly recommend that any public variables you
> declare and intended to use a property or have thought it must be
> overridden, given them as property definitions its much cleaner that way[/color]

I agree.

This was just a quick example of the what I was trying to play with. I just
wanted to make sure I was understanding what was happening correctly.

I wasn't sure if there was 1 variable or 2. I assume it was 1 and the last
defined one was the one I would see.

I heard from someone else that if I wanted 2 variables I would define it as
shadows (override being the default). I would still get the last defined
one, but I could also get the one in the base class by using the base class
name with the variable. Not sure why I would need that, but I am sure there
are good reasons for it. Right now I am just trying to get the basics of
inheritance down. I understand it, I just haven't build any objects that
were inherited by another object (other than the normal system ones).

Thanks,

Tom[color=blue]
>
> VJ
>
> "tshad" <tscheiderich@f tsolutions.com> wrote in message
> news:u$wTCq2VGH A.5808@TK2MSFTN GP12.phx.gbl...[color=green]
>>I am playing with Inheritance and want to make sure I understand it.
>>
>> I have the following Classes:
>> *************** *************** *************
>> Public Class AuthHeader:Inhe rits SoapHeader
>> Public AuthHeaderName As String
>> Public SessionKey As String = "Default"
>> End Class
>>
>> Public Class ServiceTicket:I nherits AuthHeader
>> Public IsAuthenticated As Boolean
>> Public SessionKey As String = "Default from ServiceTicket"
>> Public Expiration As DateTime
>> End Class
>>
>> Public Class TempClass1:Inhe rits ServiceTicket
>> Public TomsClass1Name As String
>> End Class
>> *************** *************** ***********
>>
>> I assume that inheritance depends on the order of definition.
>>
>> Here SessionKey is being defined in 2 classes. For TempClass1 and
>> ServiceTicket, Session would be "Default from ServiceTicket" since it
>> would have been defined second. So if I create TempClass1, it would work
>> something like, SessionKey would first be "Default" but then
>> ServiceTicket would re-define it, since it inherited it (and is higher up
>> the chain) and change it to "Default from ServiceTicket".
>>
>> In this case, if I had:
>>
>> Dim objTempClass1 As new TempClass1
>> Dim objServiceTicke t As new ServiceTicket
>> Dim objAuthHeader As new AuthHeader
>>
>> objTempClass1.S essionKey = "Default from ServiceTicket" '
>> Inherited from ServiceKey
>> objServiceKey.S essionKey = "Default from ServiceTicket"
>> objAuthHeader.S essionKey = "Default"
>>
>> But if I took out the Sessionkey from the ServiceKey class that it would
>> be:
>>
>> objTempClass1.S essionKey = "Default" ' Inherited
>> from AuthHeader
>> objServiceKey.S essionKey = "Default" ' Inherited
>> from AuthHeader
>> objAuthHeader.S essionKey = "Default"
>>
>> Also, I originally got this from a sample program that didn't set the
>> defaults, but had it defined as:
>> *************** *************** *************
>> Public Class AuthHeader:Inhe rits SoapHeader
>> Public AuthHeaderName As String
>> Public SessionKey As String
>> End Class
>>
>> Public Class ServiceTicket:I nherits AuthHeader
>> Public IsAuthenticated As Boolean
>> Public SessionKey As String
>> Public Expiration As DateTime
>> End Class
>>
>> Public Class TempClass1:Inhe rits ServiceTicket
>> Public TomsClass1Name As String
>> End Class
>> *************** *************** ***********
>>
>> Is there any good reason to defining SessionKey again ServiceTicket?
>>
>> I assume since it always would inherit from AuthHeader, it would always
>> get SessionKey from the inheritance. If it wanted to set SessionKey in
>> ServiceTicket, it could just set it by:
>>
>> SessionKey = "Default"
>>
>> without needing to redefine it.
>>
>> Is this correct?
>>
>> Thanks,
>>
>> Tom
>>
>>[/color]
>
>[/color]

**Vijay** · Apr 4 '06, 02:15 PM

Re: Inheritance

Personally I will try to avoid shadows.. as much as I can.. it just causes
confusion in readability. That is what I have seen in huge projects..

Vijay

"tshad" <tscheiderich@f tsolutions.com> wrote in message
news:eProSo3VGH A.4724@TK2MSFTN GP09.phx.gbl...[color=blue]
> "Vijay" <vijay@msdiscus sions.com> wrote in message
> news:e4p7432VGH A.4416@TK2MSFTN GP15.phx.gbl...[color=green]
>> yes the reason to override are more applicable to methods, properties
>> yes.. if you want to additional functionality to than what is available
>> in the base class.. I also strongly recommend that any public variables
>> you declare and intended to use a property or have thought it must be
>> overridden, given them as property definitions its much cleaner that way[/color]
>
> I agree.
>
> This was just a quick example of the what I was trying to play with. I
> just wanted to make sure I was understanding what was happening correctly.
>
> I wasn't sure if there was 1 variable or 2. I assume it was 1 and the
> last defined one was the one I would see.
>
> I heard from someone else that if I wanted 2 variables I would define it
> as shadows (override being the default). I would still get the last
> defined one, but I could also get the one in the base class by using the
> base class name with the variable. Not sure why I would need that, but I
> am sure there are good reasons for it. Right now I am just trying to get
> the basics of inheritance down. I understand it, I just haven't build any
> objects that were inherited by another object (other than the normal
> system ones).
>
> Thanks,
>
> Tom[color=green]
>>
>> VJ
>>
>> "tshad" <tscheiderich@f tsolutions.com> wrote in message
>> news:u$wTCq2VGH A.5808@TK2MSFTN GP12.phx.gbl...[color=darkred]
>>>I am playing with Inheritance and want to make sure I understand it.
>>>
>>> I have the following Classes:
>>> *************** *************** *************
>>> Public Class AuthHeader:Inhe rits SoapHeader
>>> Public AuthHeaderName As String
>>> Public SessionKey As String = "Default"
>>> End Class
>>>
>>> Public Class ServiceTicket:I nherits AuthHeader
>>> Public IsAuthenticated As Boolean
>>> Public SessionKey As String = "Default from ServiceTicket"
>>> Public Expiration As DateTime
>>> End Class
>>>
>>> Public Class TempClass1:Inhe rits ServiceTicket
>>> Public TomsClass1Name As String
>>> End Class
>>> *************** *************** ***********
>>>
>>> I assume that inheritance depends on the order of definition.
>>>
>>> Here SessionKey is being defined in 2 classes. For TempClass1 and
>>> ServiceTicket, Session would be "Default from ServiceTicket" since it
>>> would have been defined second. So if I create TempClass1, it would
>>> work something like, SessionKey would first be "Default" but then
>>> ServiceTicket would re-define it, since it inherited it (and is higher
>>> up the chain) and change it to "Default from ServiceTicket".
>>>
>>> In this case, if I had:
>>>
>>> Dim objTempClass1 As new TempClass1
>>> Dim objServiceTicke t As new ServiceTicket
>>> Dim objAuthHeader As new AuthHeader
>>>
>>> objTempClass1.S essionKey = "Default from ServiceTicket" '
>>> Inherited from ServiceKey
>>> objServiceKey.S essionKey = "Default from ServiceTicket"
>>> objAuthHeader.S essionKey = "Default"
>>>
>>> But if I took out the Sessionkey from the ServiceKey class that it would
>>> be:
>>>
>>> objTempClass1.S essionKey = "Default" ' Inherited
>>> from AuthHeader
>>> objServiceKey.S essionKey = "Default" ' Inherited
>>> from AuthHeader
>>> objAuthHeader.S essionKey = "Default"
>>>
>>> Also, I originally got this from a sample program that didn't set the
>>> defaults, but had it defined as:
>>> *************** *************** *************
>>> Public Class AuthHeader:Inhe rits SoapHeader
>>> Public AuthHeaderName As String
>>> Public SessionKey As String
>>> End Class
>>>
>>> Public Class ServiceTicket:I nherits AuthHeader
>>> Public IsAuthenticated As Boolean
>>> Public SessionKey As String
>>> Public Expiration As DateTime
>>> End Class
>>>
>>> Public Class TempClass1:Inhe rits ServiceTicket
>>> Public TomsClass1Name As String
>>> End Class
>>> *************** *************** ***********
>>>
>>> Is there any good reason to defining SessionKey again ServiceTicket?
>>>
>>> I assume since it always would inherit from AuthHeader, it would always
>>> get SessionKey from the inheritance. If it wanted to set SessionKey in
>>> ServiceTicket, it could just set it by:
>>>
>>> SessionKey = "Default"
>>>
>>> without needing to redefine it.
>>>
>>> Is this correct?
>>>
>>> Thanks,
>>>
>>> Tom
>>>
>>>[/color]
>>
>>[/color]
>
>[/color]

Inheritance

Inheritance

Comment

Comment

Comment