How to get text from Text Box in win32 c++ on button click?

Question

I am very new to win32 gui applications.I am trying to create simple calculator application. In that i have designed a GUI for calculator.Now i want to get text of textbox entered by user and also want to set text on click of any button i designed from 0 to 9.

For testing purpose i wrote a code to get text from textbox and tried to display it in a messagebox. But my messagebox is showing empty message. Following is my code in WinProc:

LRESULT CALLBACK WinProc(HWND hWnd,UINT msg,WPARAM wParam,LPARAM lParam)
{
    HDC hdc;
        PAINTSTRUCT ps;
        HWND B[16];// these are the saperate handles to each button in the main window.
        HWND hEditA,hEditB,hEditC;//handle for text box.
        char c[16][2]={"1","2","3","4","5","6","7","8","9","0","+","-","*","/",".","="};
        int i=0,j,x=100,y=130;
        int id[15]={1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
        int cnt;
        //char val[20];
        TCHAR val[30] = {0};
        int len;


        switch(msg)
        {
            case WM_PAINT:
                hdc=BeginPaint(hWnd,&ps);
                TextOut(hdc,10,12,"Number 1:",strlen("Number 1:")+1);
                TextOut(hdc,10,47,"Number 2:",strlen("Number 2:")+1);
                TextOut(hdc,10,87,"Result  :",strlen("Result  :")+1);
                //  TextOut(hdc,10,100,"hellow sachin",strlen("hello sachin")+1);
                EndPaint(hWnd,&ps);
                break;

            case WM_DESTROY:
                PostQuitMessage (0);
                break;

            case WM_CREATE:

                            hEditA=CreateWindow(TEXT("Edit"), TEXT(""), WS_CHILD | WS_VISIBLE | WS_BORDER|ES_NUMBER|ES_RIGHT, 100, 10, 150, 25, hWnd, NULL, NULL, NULL);
                            hEditB=CreateWindow(TEXT("Edit"), TEXT(""), WS_CHILD | WS_VISIBLE | WS_BORDER|ES_NUMBER|ES_RIGHT, 100, 45, 150, 25, hWnd, NULL, NULL, NULL);
                            hEditC=CreateWindow(TEXT("Edit"), TEXT(""), WS_CHILD | WS_VISIBLE | WS_BORDER|ES_NUMBER|ES_RIGHT, 100, 85, 150, 25, hWnd, NULL, NULL, NULL);
                            cnt=0;
                            for(i=0;i<16;i++)
                            {
                                if(cnt==4)
                                {
                                    y=y+40;
                                    x=100;
                                    cnt=0;


                                }

                                if(cnt<4)
                                {
                                    B[i] =   CreateWindow(TEXT("button"), TEXT(c[i]),    
                                         WS_VISIBLE | WS_CHILD | BS_PUSHBUTTON,
                                         x, y, 30, 30,        
                                         hWnd, (HMENU) id[i], NULL, NULL);
                                    x=x+40;
                                    //y=y+30;
                                    cnt++;

                                }
                            }

            case WM_COMMAND:

                    switch(LOWORD(wParam))
                    {
                        case 1:
                                len=GetWindowText( hEditA,val,10);
                               MessageBox(hWnd,(LPSTR)val, "Info", MB_OK); 
                                SetWindowText( hEditB,val);




                               break;
                                    }
    }
}

B. I also want to display the caption of the button pressed in the textbox.

So please can anyone help me to find the way to correct it.

thanx in advance..

Answer 1

This should get the text for you:

SendMessage(hEditA, WM_GETTEXT, (WPARAM)10, (LPARAM)val);

Are those window handles defined in the scope of the window procedure, or global? If they are defined in the scope of the window procedure, they will be forgotten after WM_CREATE returns control to the Operating System.

If they are defined in the window procedure, try:

static HWND hEditA, ...

EDIT: You should also break from your WM_CREATE handler, as it will fall through to your WM_COMMAND handler.