Problems with the contructor/new() method in the subclass

[Antuane]

I've got a class as follows,

PUBLIC CLASS BaseClass

Sub New()
End Sub

Sub New(byval cName as String)
End Sub

Sub New(byval cName as String, nAge as Int16)
End Sub

END CLASS

PUBLIC CLASS Person
Inherits BaseClass
END CLASS
** Coding
If suppose i try the following piece of coding,
Dim oPerson as New Person("Jack", "Daniels")

"Then i get an error saying that the NEW method cannot accecpt so may
parameters

1. What have i done wrong?
2. I want to define such base NEW() - constructors, & do'nt want to write
these coding out in the subclasses.
But it seems taht i have to do so.

2. Is is possible for me to restrict the Sub NEW() contructor - the one
wihout parameters.
i.e. what i want to do is, when initializing the Person class, i want to
make it impossible to initialize this class by using the New() constructor
without any paramters.
Right now, what i do is,

PUBLIC CLass Person
Sub New()
THROW New Exception("Try using the Other Constructors which
accept parameters")
End Sub
.....

Is there another way of achieving the above?????

[Herfried K. Wagner [MVP]]

"Antuane" <An*****@testing.com.net> schrieb:

I've got a class as follows,

PUBLIC CLASS BaseClass

Sub New()
End Sub

Sub New(byval cName as String)
End Sub

Sub New(byval cName as String, nAge as Int16)
End Sub

END CLASS

PUBLIC CLASS Person
Inherits BaseClass
END CLASS
** Coding
If suppose i try the following piece of coding,
Dim oPerson as New Person("Jack", "Daniels")

"Then i get an error saying that the NEW method cannot accecpt so may
parameters

1. What have i done wrong?
2. I want to define such base NEW() - constructors, & do'nt want to write
these coding out in the subclasses.
But it seems taht i have to do so.
Constructors defined in the base class are not inherited automatically. You
will have to add them to the base class too:

\\\
..
..
..
Sub New(byval cName as String, nAge as Int16)
MyBase.New(cName, nAge)
End Sub
..
..
..
///
2. Is is possible for me to restrict the Sub NEW() contructor - the one
wihout parameters.
i.e. what i want to do is, when initializing the Person class, i want
to
make it impossible to initialize this class by using the New() constructor
without any paramters.
Right now, what i do is,

PUBLIC CLass Person
Sub New()
THROW New Exception("Try using the Other Constructors which
accept parameters")
End Sub

Why do you add a parameterless ctor at all (assuming you add parameterized
ctors too)?

--
Herfried K. Wagner [MVP]
<URL:http://dotnet.mvps.org/>

[Larry Serflaten]

Comments inline....

"Antuane" <An*****@testing.com.net> wrote

<snipped for brievity>

** Coding
If suppose i try the following piece of coding,
Dim oPerson as New Person("Jack", "Daniels")

"Then i get an error saying that the NEW method cannot accecpt so may
parameters

1. What have i done wrong?
You did not supply New routines in your derived class. It is a class itself,
and it needs constructors just like your base class.

2. I want to define such base NEW() - constructors, & do'nt want to write
these coding out in the subclasses.
Then try Copy and Paste? Really, you have to have them out there if you
want that class to accept parameters during construction.
But it seems taht i have to do so.
Correct.


2. Is is possible for me to restrict the Sub NEW() contructor - the one
wihout parameters.
Yes.
Is there another way of achieving the above?????
Make that constructor private:
Public Class Person
PRIVATE Sub New()
' Being private, only code in this class can use this routine.
End Sub

Have fun!
LFS