class must only be used as a base class

[Steve Richter]

I have a class, "BaseUserTable", that must be derived from to be used
correctly:

class BaseUserTable
{
public virtual string TableName
{
get { throw( new ApplicationException( "where's the TableName
property in the derived class??" )) ; }
}
}

( the idea is that BaseUserTable contains methods for managing the
UserTable, only an application that uses the class must supply the
actual table name and database connection string. )

How do I do this in c#/.net? I want derived classes to get a compile
error if they dont implement the required virtual methods and
properties.

I am curious if an interface can do the trick. I just dont want to have
to implement the interface in this base class.

thanks,

-Steve

[rmacias]

What you probably want to do is create an abstract class. Add the keyword
"abstract" before your class definition. This will mean that your class can
not be instantiated and only be derived.

http://msdn.microsoft.com/library/de...actclasses.asp
"Steve Richter" wrote:

I have a class, "BaseUserTable", that must be derived from to be used
correctly:

class BaseUserTable
{
public virtual string TableName
{
get { throw( new ApplicationException( "where's the TableName
property in the derived class??" )) ; }
}
}

( the idea is that BaseUserTable contains methods for managing the
UserTable, only an application that uses the class must supply the
actual table name and database connection string. )

How do I do this in c#/.net? I want derived classes to get a compile
error if they dont implement the required virtual methods and
properties.

I am curious if an interface can do the trick. I just dont want to have
to implement the interface in this base class.

thanks,

-Steve

[Lebesgue]

You may want to make the base class abstract (methods that have to be
overriden as well)

abstract class Foo
{
public abstract void Do();
}

class Bar : Foo
{
public override void Do()
{
//do foo
}
}

"Steve Richter" <St************@gmail.com> wrote in message
news:11**********************@z14g2000cwz.googlegr oups.com...

I have a class, "BaseUserTable", that must be derived from to be used
correctly:

class BaseUserTable
{
public virtual string TableName
{
get { throw( new ApplicationException( "where's the TableName
property in the derived class??" )) ; }
}
}

( the idea is that BaseUserTable contains methods for managing the
UserTable, only an application that uses the class must supply the
actual table name and database connection string. )

How do I do this in c#/.net? I want derived classes to get a compile
error if they dont implement the required virtual methods and
properties.

I am curious if an interface can do the trick. I just dont want to have
to implement the interface in this base class.

thanks,

-Steve

[Steve Richter]

rmacias wrote:

What you probably want to do is create an abstract class. Add the keyword
"abstract" before your class definition. This will mean that your class can
not be instantiated and only be derived.

http://msdn.microsoft.com/library/de...actclasses.asp

perfect!

thanks,

-Steve


"Steve Richter" wrote:

I have a class, "BaseUserTable", that must be derived from to be used
correctly:

class BaseUserTable
{
public virtual string TableName
{
get { throw( new ApplicationException( "where's the TableName
property in the derived class??" )) ; }
}
}

( the idea is that BaseUserTable contains methods for managing the
UserTable, only an application that uses the class must supply the
actual table name and database connection string. )

How do I do this in c#/.net? I want derived classes to get a compile
error if they dont implement the required virtual methods and
properties.

I am curious if an interface can do the trick. I just dont want to have
to implement the interface in this base class.

thanks,

-Steve

[Ignacio Machin \( .NET/ C# MVP \)]

Hi,

Just declare the base class as abstract. Another way to avoid the creation
of a class is declaring the constructor as private , in this way you cannot
create an instance of it.
cheers,

--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

"Steve Richter" <St************@gmail.com> wrote in message
news:11**********************@z14g2000cwz.googlegr oups.com...

I have a class, "BaseUserTable", that must be derived from to be used
correctly:

class BaseUserTable
{
public virtual string TableName
{
get { throw( new ApplicationException( "where's the TableName
property in the derived class??" )) ; }
}
}

( the idea is that BaseUserTable contains methods for managing the
UserTable, only an application that uses the class must supply the
actual table name and database connection string. )

How do I do this in c#/.net? I want derived classes to get a compile
error if they dont implement the required virtual methods and
properties.

I am curious if an interface can do the trick. I just dont want to have
to implement the interface in this base class.

thanks,

-Steve