Adding items in list box using win32 API

Question

0.00/5 (No votes)

See more:

Sir, I have created a list box in Win32 API like this

C++

// list1 is HWND variable
list1 = CreateWindow(L"LISTBOX", NULL, WS_CHILDWINDOW | WS_VISIBLE | LBS_STANDARD,10,150,330,200, hWnd, (HMENU)ID_LISTBOX,hInst, NULL);

It does created successfully. To avoid confusion I've used several cplusplus files. I have created a class in the separate header file and defined it in a separate cpp file. By using the header file I've called the member functions using objects in my main cpp file.

But the problem is sir one of member function should add strings to the list. I know it can be achieved by SendMessage function when everything is in the same cpp file. Since my class is in the different .cpp file I can't do this.

What I have tried:

1. Made list1 as a global variable by adding my variable before the forward declarations of functions included in my code module.

When I do like this I am getting "uninitialized variable error"

2. Did moved the variable to a new header file and made it accessible to both cpp files

I got "Multiple declarations of variable" error

3. I need of something like the variable to be used and defined somewhere else so I made use of storage classes ("extern" in this case) but when using extern I get a strange error in the object file. I am quiet sure object file can't be read by humans so I did completely stopped researching aboout this error and the usage of extern variables.

C++

Severity	Code	Description	Project	File	Line
Error	LNK2005	"struct HWND__ * list1" (?list1@@3PAUHWND__@@A) already defined in Portable Devices Manager.obj	 Portable Devices Manager	G:\Portable Devices Manager\Portable Devices Manager\ShortCutVirusKiller.obj

Kindly help me with this sir please

Posted 16-Mar-16 23:33pm

VISWESWARAN1998

Updated 16-Mar-16 23:54pm

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

CPallini · Accepted Answer · 2016-03-16T23:54:00

Solution 1

declare your variable as extern in a header file, e.g.

C

// mylist.h
extern HWND  hwndMyList;

define it in just one source file, e.g.

C

// mylist.cpp
// ...
HWND hwndMyList;
// ...

include the header file in all the other sources needing the variable

C

// foo.cpp
#include "mylist.h"
//...
hwndMyList = CreateWindow(/*...*/);
//...

Posted 16-Mar-16 23:54pm

CPallini

Comments

[no name] 17-Mar-16 6:33am

Thank you sir for your kind help and time. I defined my variable in multiple source files like defining "functions". I think that was the error.
Thank you once again sir

CPallini 17-Mar-16 6:54am

You are welcome.

Arthur V. Ratz 21-Mar-16 3:13am

+5.

CPallini 21-Mar-16 4:19am

Thank you.