Re: Unable to declare a class in 2 forms

From:
David Wilkinson <no-reply@effisols.com>
Newsgroups:
microsoft.public.dotnet.languages.vc
Date:
Sat, 26 Sep 2009 08:30:45 -0400
Message-ID:
<##OLpUqPKHA.1236@TK2MSFTNGP05.phx.gbl>
Allen wrote:

Unable to declare a class in 2 forms

--------------------------------------------------------------------------------

Below are 4 forms. Namely: Form1, EmployeeID, AboutBox and
EnterEmployeeName. I made a class to help in open, write and read from
files, called Time. I managed to declare class Time in EmployeeID space,
but could not declare it in EnterEmployeeName. In other words, I can
declare class Time in one space only. I realy want to use class Time in
both forms, EmployeeID and EnterEmployeeName. Can anybody tell me why I
always get error, below, every time I run the program? And how can I use
the Time class in both the above forms? I am showing below the skeleton
and believe me it will compile.

Error message:

1>c:\users\allen\documents\visual studio
2008\projects\timetracking\timetracking\Time.h(5) : error C2011: 'Time'
: 'class' type redefinition
1> c:\users\allen\documents\visual studio
2008\projects\timetracking\timetracking\Time.h(5) : see declaration of
'Time'
1>EnterEmployeeName.cpp

//Form1:

#pragma once
#include "AboutBox.h"
#include "EmployeeID.h"
#include "EnterEmployeeName.h"
namespace TimeTracking
{
using namespace System::Windows::Forms;
public ref class Form1 : public System::Windows::Forms::Form
{

};
}
/***************************/

// EmployeeID

#pragma once
#include "Time.h"
//#include "stdafx.h"
#using <mscorlib.dll>

namespace TimeTracking
{
public ref class EmployeeID : public System::Windows::Forms::Form
{
};
}
/***************************/

// AboutBox:

#pragma once
namespace TimeTracking
{
public ref class AboutBox : public System::Windows::Forms::Form
{

};
}
/***************************/

//EnterEmployeeName:

#pragma once
#include "stdafx.h"
//#include "Time.h" //???-------------uncomment and get error C2011

namespace TimeTracking
{

public ref class EnterEmployeeName : public System::Windows::Forms::Form
{

};
}
/***************************/

//Time.h:

using namespace System;
ref class Time
{
};
/***************************/

//Time.cpp:

#include "stdafx.h"
#include "Time.h"
#using <mscorlib.dll>


Allen:

1. Time.h (and all header files) need #pragma once at the beginning.

2. Do not use #include "stdafx.h" in header files.

3. #include "stdafx.h" must be the first line in all .cpp files.

--
David Wilkinson
Visual C++ MVP

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