translate c# to c++

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

thwei - 14 Jul 2004 17:07 GMT

How to translate this to c++

public new Bar this[int nIndex]

{

get{ return (Bar)base[nIndex]; }

}

Reply to this Message

Brandon Bray [MSFT] - 14 Jul 2004 19:31 GMT

> How to translate this to c++
>
[quoted text clipped - 5 lines]
>
> }

In the new C++ syntax, this translates to (assuming Bar is a ref class):

property Bar^ default [int] {
Bar^ get(int nIndex) { return (Bar^)BaseClassName::default[nIndex]; }
}

In the old syntax, it would be something like this:

__property Bar* get_Item(int nIndex) {
return __try_cast<Bar*>(this->BaseClassName::Item[nIndex]; }
}

In the old syntax, you also need to put this attribute on the containing
__gc class: [System::Reflection::DefaultMember(S"Item")]

Signature

Brandon Bray, Visual C++ Compiler http://blogs.msdn.com/branbray/
This posting is provided AS IS with no warranties, and confers no rights.

Reply to this Message

thwei - 14 Jul 2004 20:52 GMT

> In the old syntax, it would be something like this:
>
[quoted text clipped - 4 lines]
> In the old syntax, you also need to put this attribute on the containing
> __gc class: [System::Reflection::DefaultMember(S"Item")]

Type Item of base class is Object and this generated Error C2392 "covariant
returns types are not supported in managed types"

Reply to this Message

Brandon Bray [MSFT] - 17 Jul 2004 00:45 GMT

> Type Item of base class is Object and this generated Error C2392
> "covariant returns types are not supported in managed types"

Then the property type needs to be Object. The CLR doesn't support covariant
returns from virtual functions.

Signature

Brandon Bray, Visual C++ Compiler http://blogs.msdn.com/branbray/
This posting is provided AS IS with no warranties, and confers no rights.

Reply to this Message

Hasani \(remove nospam from address\) - 14 Jul 2004 20:26 GMT

Assuming the class that contains that property derives from a class called
Bar.

[System::Reflection::DefaultMember(S"Item")]
public __gc class Bar
{
public:
__property Bar* get_Item(int index)
{
return NULL;
}
};

public __gc class Foo : public Bar
{
public:
__property Bar* get_Item(int index)
{
return Bar::get_Item(index);
}
};

> How to translate this to c++
>
[quoted text clipped - 5 lines]
>
> }

Reply to this Message

thwei - 14 Jul 2004 20:43 GMT

U?ytkownik "Hasani (remove nospam from address)"
<hblackwell@n0sp4m.popstick.com> napisa? w wiadomo?ci
news:eXzJJidaEHA.3988@tk2msftngp13.phx.gbl...

> Assuming the class that contains that property derives from a class called
> Bar.
[quoted text clipped - 17 lines]
> }
> };

Yes, but this one problem:
public __gc class Bar
{
public:
__property Object* get_Item(int index)
{
return NULL;
}
};

public __gc class Foo : public Bar
{
public:
__property Bar* get_Item(int index) //Error C2392 covariant returns types
are not supported in managed types
{
return Bar::get_Item(index);
}
};

Exactly:

public __gc class Foo : public ArrayList
{
public:
__property Bar* get_Item(int index) //Error C2392 covariant returns types
are not supported in managed types
{
return Bar::get_Item(index);
}
};

Reply to this Message

Hasani \(remove nospam from address\) - 14 Jul 2004 21:16 GMT

If you're intention is to derive Foo from ArrayList, you should instead
derive from CollectionBase. The problem is, an array list can store anything
derived from System.Object. In c#, you can use the 'new' keyword to overload
a method, but if your derived class is casted to an IList or an ArrayList,
nothing is to stop the user from calling IList[X] = Foo, or ArrayList[Y] =
Y.

> U?ytkownik "Hasani (remove nospam from address)"
> <hblackwell@n0sp4m.popstick.com> napisa? w wiadomo?ci
[quoted text clipped - 52 lines]
> }
> };

Reply to this Message

thwei - 15 Jul 2004 09:17 GMT

Thanks. Its must derived over CollectionBase and work ok. Thanks again.

U?ytkownik "Hasani (remove nospam from address)"
<hblackwell@n0sp4m.popstick.com> napisa? w wiadomo?ci
news:OnESF%23daEHA.3112@tk2msftngp13.phx.gbl...

> If you're intention is to derive Foo from ArrayList, you should instead
> derive from CollectionBase. The problem is, an array list can store anything
> derived from System.Object. In c#, you can use the 'new' keyword to overload
> a method, but if your derived class is casted to an IList or an ArrayList,
> nothing is to stop the user from calling IList[X] = Foo, or ArrayList[Y] =
> Y.

Reply to this Message

translate c# to c++

Free Magazines