Inherit an interface in managed C++

[john conwell]

I'm trying to make a class that already inherits from a base class, also
inherit from an interface in managed C++.

so my interface looks like so:

__gc interface ITask
{
__property String* get_Subject();
};

and the class that inherits from it is defined like so:

public __gc class Message : public MsgObject, public ITask {

and the get_Subject property in the header file for Message looks like so:

__property String* get_Subject();

but no matter what i try, i cant get it to compile. I've played with every
combination of __gc, interface, __interface, public or not and no luck.

mostly i get a compile error stating that my Message class can only inherit
from one base class. but i've got the ITask defined as an interface. any
ideas?

thanks.

[john conwell]

ok...so i figured out i was miss-defining my interface. the following works
just fine:

public __gc __interface ITask
{
public public:
__property String* get_Subject();
__property String* get_Text();
};

I was basically missing the "public public", which leads me to my next
question: What in the heck does "public public" mean. Its doubly public. is
"public public public" even more public? ;-)

seriouslyl though...what is the double public thing for?

"john conwell" wrote:

I'm trying to make a class that already inherits from a base class, also
inherit from an interface in managed C++.

so my interface looks like so:

__gc interface ITask
{
__property String* get_Subject();
};

and the class that inherits from it is defined like so:

public __gc class Message : public MsgObject, public ITask {

and the get_Subject property in the header file for Message looks like so:

__property String* get_Subject();

but no matter what i try, i cant get it to compile. I've played with every
combination of __gc, interface, __interface, public or not and no luck.

mostly i get a compile error stating that my Message class can only inherit
from one base class. but i've got the ITask defined as an interface. any
ideas?

thanks.

[Peter Oliphant]

I think your problem is (and I'm having the same problem with my code) is
that MANAGED code doesn't allow MULTIPLE-inheritance.

So:

public __gc class Message : public MsgObject, public ITask ...

just won't work... (sorry, I wish it did, would save me lots of extra work
too...hehe)

"john conwell" <jo*********@discussions.microsoft.com> wrote in message
news:B7**********************************@microsof t.com...

ok...so i figured out i was miss-defining my interface. the following
works
just fine:

public __gc __interface ITask
{
public public:
__property String* get_Subject();
__property String* get_Text();
};

I was basically missing the "public public", which leads me to my next
question: What in the heck does "public public" mean. Its doubly public.
is
"public public public" even more public? ;-)

seriouslyl though...what is the double public thing for?

"john conwell" wrote:

I'm trying to make a class that already inherits from a base class, also
inherit from an interface in managed C++.

so my interface looks like so:

__gc interface ITask
{
__property String* get_Subject();
};

and the class that inherits from it is defined like so:

public __gc class Message : public MsgObject, public ITask {

and the get_Subject property in the header file for Message looks like
so:

__property String* get_Subject();

but no matter what i try, i cant get it to compile. I've played with
every
combination of __gc, interface, __interface, public or not and no luck.

mostly i get a compile error stating that my Message class can only
inherit
from one base class. but i've got the ITask defined as an interface.
any
ideas?

thanks.

[john conwell]

It doesnt allow multiple class inheritance, but you can inherit from as many
interfaces as you want. I figured out the problem, i just cant find any info
on what "public public" is for in the interface definition

"Peter Oliphant" wrote:

I think your problem is (and I'm having the same problem with my code) is
that MANAGED code doesn't allow MULTIPLE-inheritance.

So:

public __gc class Message : public MsgObject, public ITask ...

just won't work... (sorry, I wish it did, would save me lots of extra work
too...hehe)

"john conwell" <jo*********@discussions.microsoft.com> wrote in message
news:B7**********************************@microsof t.com...

ok...so i figured out i was miss-defining my interface. the following
works
just fine:

public __gc __interface ITask
{
public public:
__property String* get_Subject();
__property String* get_Text();
};

I was basically missing the "public public", which leads me to my next
question: What in the heck does "public public" mean. Its doubly public.
is
"public public public" even more public? ;-)

seriouslyl though...what is the double public thing for?

"john conwell" wrote:

I'm trying to make a class that already inherits from a base class, also
inherit from an interface in managed C++.

so my interface looks like so:

__gc interface ITask
{
__property String* get_Subject();
};

and the class that inherits from it is defined like so:

public __gc class Message : public MsgObject, public ITask {

and the get_Subject property in the header file for Message looks like
so:

__property String* get_Subject();

but no matter what i try, i cant get it to compile. I've played with
every
combination of __gc, interface, __interface, public or not and no luck.

mostly i get a compile error stating that my Message class can only
inherit
from one base class. but i've got the ITask defined as an interface.
any
ideas?

thanks.

[Ronald Laeremans [MSFT]]

john conwell wrote:

ok...so i figured out i was miss-defining my interface. the following works
just fine:

public __gc __interface ITask
{
public public:
__property String* get_Subject();
__property String* get_Text();
};

I was basically missing the "public public", which leads me to my next
question: What in the heck does "public public" mean. Its doubly public. is
"public public public" even more public? ;-)

seriouslyl though...what is the double public thing for?

"john conwell" wrote:

I'm trying to make a class that already inherits from a base class, also
inherit from an interface in managed C++.

so my interface looks like so:

__gc interface ITask
{
__property String* get_Subject();
};

and the class that inherits from it is defined like so:

public __gc class Message : public MsgObject, public ITask {

and the get_Subject property in the header file for Message looks like so:

__property String* get_Subject();

but no matter what i try, i cant get it to compile. I've played with every
combination of __gc, interface, __interface, public or not and no luck.

mostly i get a compile error stating that my Message class can only inherit
from one base class. but i've got the ITask defined as an interface. any
ideas?

thanks.

It should work with just one "public" there.

public public:
is a synonym for
public:

If you use 2 then the most restrictive one is for access outside the
assembly and the least restrictive one is for access inside the assembly.

E.g.

public private:

Means that any class in the assembly can access the members defiend
after this but no class outside of the assembly can.

Ronald

[john conwell]

Eurika!!!

thanks dude

"Ronald Laeremans [MSFT]" wrote:

john conwell wrote:

ok...so i figured out i was miss-defining my interface. the following works
just fine:

public __gc __interface ITask
{
public public:
__property String* get_Subject();
__property String* get_Text();
};

I was basically missing the "public public", which leads me to my next
question: What in the heck does "public public" mean. Its doubly public. is
"public public public" even more public? ;-)

seriouslyl though...what is the double public thing for?

"john conwell" wrote:

I'm trying to make a class that already inherits from a base class, also
inherit from an interface in managed C++.

so my interface looks like so:

__gc interface ITask
{
__property String* get_Subject();
};

and the class that inherits from it is defined like so:

public __gc class Message : public MsgObject, public ITask {

and the get_Subject property in the header file for Message looks like so:

__property String* get_Subject();

but no matter what i try, i cant get it to compile. I've played with every
combination of __gc, interface, __interface, public or not and no luck.

mostly i get a compile error stating that my Message class can only inherit
from one base class. but i've got the ITask defined as an interface. any
ideas?

thanks.

It should work with just one "public" there.

public public:
is a synonym for
public:

If you use 2 then the most restrictive one is for access outside the
assembly and the least restrictive one is for access inside the assembly.

E.g.

public private:

Means that any class in the assembly can access the members defiend
after this but no class outside of the assembly can.

Ronald