Exposing a "null" dotnet object

[Peter Hemmingsen]

Hi,

I have a dotnet object (implemented in mc++ and used in c#) which have a
property called "Info". The Info property is also a dotnet object
(implemented in mc++). In the constructor of the "main" object I want to
initialize the property "Info" to null in a way that will make the c#
programmer (the user) able to write:

if (MyObj.Info==null) {..}

I've tried to initialize the Info property (in mc++) as follows:

this->Info=0; // Note Info is a __gc class pointer

but the above c# code always returns false.

Any suggestions?

Peter

[Nishant S]

Strange. I could not reproduce this problem.

MC++ class library :-

namespace mcpp_del
{
public __gc class Class1
{
public:
Object* GetObj()
{
Object* o = 0;
return o;
}
};
}

C# program :-

using System;
using mcpp_del;

namespace ConsoleApplication4
{
class Class2
{
[STAThread]
static void Main(string[] args)
{
Class1 c1 = new Class1();
Console.WriteLine(c1.GetObj() == null);
}
}
}

The output is :-

True

--
Regards,
Nish [VC++ MVP]

"Peter Hemmingsen" <ph*@softco.dk> wrote in message
news:Oz**************@TK2MSFTNGP12.phx.gbl...

Hi,

I have a dotnet object (implemented in mc++ and used in c#) which have a
property called "Info". The Info property is also a dotnet object
(implemented in mc++). In the constructor of the "main" object I want to
initialize the property "Info" to null in a way that will make the c#
programmer (the user) able to write:

if (MyObj.Info==null) {..}

I've tried to initialize the Info property (in mc++) as follows:

this->Info=0; // Note Info is a __gc class pointer

but the above c# code always returns false.

Any suggestions?

Peter

[Yan-Hong Huang[MSFT]]

Hello Peter,

Thanks for posting in the group. I have tested it on my side and got the
same result as Nish.

I have replied this question in dotnet.languages.vc group. Could you please
check it when you have free time? I will follow up you there.

Best regards,
Yanhong Huang
Microsoft Online Partner Support

Get Secure! - www.microsoft.com/security
This posting is provided "AS IS" with no warranties, and confers no rights.

--------------------
!From: "Peter Hemmingsen" <ph*@softco.dk>
!Subject: Exposing a "null" dotnet object
!Date: Thu, 11 Sep 2003 16:44:06 +0200
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!X-Tomcat-NG: microsoft.public.dotnet.languages.csharp
!
!Hi,
!
!I have a dotnet object (implemented in mc++ and used in c#) which have a
!property called "Info". The Info property is also a dotnet object
!(implemented in mc++). In the constructor of the "main" object I want to
!initialize the property "Info" to null in a way that will make the c#
!programmer (the user) able to write:
!
!if (MyObj.Info==null) {..}
!
!I've tried to initialize the Info property (in mc++) as follows:
!
!this->Info=0; // Note Info is a __gc class pointer
!
!but the above c# code always returns false.
!
!Any suggestions?
!
!Peter
!
!
!
!
!
!