NULL undeclared identifier !

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tlemcenvisit - 15 Jun 2005 13:10 GMT

Hello
I'd like to clear a picturebox
I used
pictureBox1->Image=NULL;
but I obtained
NULL undeclared identifier
please, what is the problem?

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Jochen Kalmbach [MVP] - 15 Jun 2005 15:39 GMT

Hi tlemcenvisit!

> I'd like to clear a picturebox
> I used
> pictureBox1->Image=NULL;
> but I obtained
> NULL undeclared identifier
> please, what is the problem?

#include <windows.h>

But if this is managed-C++ you should just use "0".

For VC2005 you can also use "null".

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Greetings
Jochen

My blog about Win32 and .NET
http://blog.kalmbachnet.de/

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tlemcenvisit - 15 Jun 2005 17:29 GMT

I'm in VC++2005 (managed C++) and I used 'null' , then I obtained the same
think 'null undeclared identifier' and when I used '0' I obtained 'cannot
convert from 'int' to 'System::Drawing::Image ^''
Please, what is the problem?

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Carl Daniel [VC++ MVP] - 15 Jun 2005 17:40 GMT

> I'm in VC++2005 (managed C++) and I used 'null' , then I obtained the
> same think 'null undeclared identifier' and when I used '0' I
> obtained 'cannot convert from 'int' to 'System::Drawing::Image ^''
> Please, what is the problem?

use nullptr instead of null (which is the C# keyword).

-cd

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Jochen Kalmbach [MVP] - 15 Jun 2005 18:46 GMT

Hi Carl!

>>I'm in VC++2005 (managed C++) and I used 'null'
>
> use nullptr instead of null (which is the C# keyword).

Yes, sorry... I was forgot "ptr"...

Signature

Greetings
Jochen

My blog about Win32 and .NET
http://blog.kalmbachnet.de/

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Tamas Demjen - 15 Jun 2005 17:44 GMT

In VC++2005 you should use 'nullptr'.

Tom

> I'm in VC++2005 (managed C++) and I used 'null' , then I obtained the same
> think 'null undeclared identifier' and when I used '0' I obtained 'cannot
> convert from 'int' to 'System::Drawing::Image ^''
> Please, what is the problem?

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NULL undeclared identifier !

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