Win32 C++ GUI - take inputed text and show it in another window

[malcolmsand]

Hello guys,

I have a problem with Win32 C++ GUI. I'm creating a program and as one of the steps, I want to:
1. Let the user type somthing in the textbox,
2. Show it in another box/area,
3. Clear the typed text from the textbox.

It would be something like chat - in one window you type the message and it's shown in the second one.

So far, I have code with 2 windows (not much, I know) and I know that inside WM_COMMAND I should have some code that will take the inputed text and then will pass it to another window (where I want to show messages).

Here is my code:

#if defined(UNICODE) && !defined(_UNICODE)
    #define _UNICODE
#elif defined(_UNICODE) && !defined(UNICODE)
    #define UNICODE
#endif

#include <tchar.h>
#include <windows.h>

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

/*  Make the class name into a global variable  */
TCHAR szClassName[ ] = _T("CodeBlocksWindowsApp");
HWND TextBox, SendButton, TextField;


int WINAPI WinMain (HINSTANCE hThisInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR lpszArgument,
                     int nCmdShow)
{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default colour as the background of the window */
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;

    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
           0,                   /* Extended possibilites for variation */
           szClassName,         /* Classname */
           _T("Messages"),       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           500,                 /* The programs width */
           370,                 /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, nCmdShow);

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)                  /* handle the messages */
    {
        case WM_CREATE:

            TextBox = CreateWindow("EDIT",
                                   "",
                                   WS_BORDER | WS_CHILD | WS_VISIBLE,
                                   10, 300, 390, 20,
                                   hwnd, (HMENU) 1, NULL, NULL);

            SendButton = CreateWindow("BUTTON",
                         "Send",
                         WS_VISIBLE | WS_CHILD | WS_BORDER,
                         410, 300, 65, 20,
                         hwnd, (HMENU) 2, NULL, NULL);

            TextField = CreateWindow("EDIT",
                                     "",
                                     WS_VISIBLE | WS_CHILD | WS_BORDER | ES_READONLY,
                                     10, 90, 465, 200,
                                     hwnd, (HMENU) 3, NULL, NULL);
            break;

        case WM_COMMAND:
            switch(LOWORD(wParam))
            {
                case 1: // when button is clicked, this will happen:

                // what code should go here??

                break;
            }
        break;

        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}

I will be very gratefull for helping me which functions I should use there or if you would be so helpful to add some code.

[triumphost]

I don't understand what problem you are having doing this.. What have you tried :S

The solution is below:

//Get the text from box 1.
int len = GetWindowTextLength(TextBox) + 1;
char* text = new char[len];
GetWindowText(TextBox, &text[0], len);

//Append the text to box 2.
SendMessage(TextField, EM_SETSEL, -1, -1);
SendMessage(TextField, EM_REPLACESEL, 0, (LPARAM)&text[0]);
delete[] text;

//Delete the text from box 1.
SetWindowText(TextBox, "");

If you don't want to append the text then just use SetWindowText(TextField, text);

I've tested this before in my own chat program.

[malcolmsand]

triumphost, it works perfectly, thank you very much for help.

If it's possible, I have another question: What should I do if I'd like to put each new message in a new line?

[triumphost]

To put a message on a new line, you must affix \r\n to the end of the previous string OR to the beginning or the new string and THEN append the result to your textbox.