Thread: Drop-down box

Damn, I always ask 1 minute before I find the answer by myself. I didn't know they are called "combo boxes"...
But still, it works only when I use it with some listbox styles:

Code:

f1=CreateWindowEx(0,"Combobox","The first one",WS_BORDER|WS_VISIBLE|WS_CHILD|LBS_STANDARD|LBS_USETABSTOPS,10,10,100,200,hwnd,(HMENU)25554,GetModuleHandle(NULL),NULL);

Without LBS_STANDARD it won't display correctly...

How can I get the data of the currently selected string?

Code:

MessageBox(hwnd,(char*)SendMessage(f1,CB_GETITEMDATA,SendMessage(f1,CB_GETCURSEL,0,0),0),TEXT("hello"),MB_OK);

Doesn't seem to work...
Tried this too:

Code:

char* happy;
happy=(char*)SendMessage(f1,CB_GETCURSEL,0,0);
SendMessage(f1,CB_GETLBTEXT,(WPARAM)happy,(LPARAM)happy);
MessageBox(hwnd,happy,TEXT("hello"),MB_OK);

But this crashes my program...
Ok tested a bit and found a working way:

Code:

int tap;
char hello[256];
tap=(int)SendMessage(f1,CB_GETCURSEL,0,0);
SendMessage(f1,CB_GETLBTEXT,(WPARAM)tap,(LPARAM)happy);
MessageBox(hwnd,happy,TEXT("hello"),MB_OK);

good call on that GetWindowText( ) function.. was just having the same problem.. but now I can easily extract selected text from my combo box

Code:

#include <windows.h>

#define ID_LIST 1
#define ID_TEXT 2

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

/*  Make the class name into a global variable  */
char szClassName[ ] = "ComboBox App";

int WINAPI WinMain (HINSTANCE hThisInstance,
                    HINSTANCE hPrevInstance,
                    LPSTR lpszArgument,
                    int nFunsterStil)

{
    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 color 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 */
           "ComboBox App",       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           544,                 /* The programs width */
           375,                 /* 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, nFunsterStil);

    /* 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;
}


//User Defined Function(s)

//Compare the efficiency of my C++ function vs. Charles Petzold's C function  
//Page #407
void FillListBox(HWND hwndList)
{
     TCHAR *pVarName[] = {"Item1", "Item2", "Item3", "Item4", "Item5"};
     
     for(int i=0; i<5; i++)
  
             SendMessage(hwndList, CB_ADDSTRING, 0, (LPARAM)pVarName[i]);
     
}
             



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

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static HWND hwndList, hwndText;
    int iIndex, iLength, cxChar, cyChar;
    TCHAR pVarName[30];
        
     
        
    switch (message)                  /* handle the messages */
    {
    
        case WM_CREATE:
             
             cxChar = LOWORD(GetDialogBaseUnits());
             cyChar = HIWORD(GetDialogBaseUnits());
             
           //Create Display Window
           hwndText = CreateWindow(TEXT("static"),NULL, WS_CHILD | WS_VISIBLE |
                                   SS_LEFT, cxChar, cyChar, 
                                   GetSystemMetrics(SM_CXSCREEN), cyChar, 
                                   hwnd, (HMENU)ID_TEXT, 
                                   (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE), 
                                   NULL);
             
           //Create ComboBox
           hwndList =  CreateWindow(TEXT("Combobox"), NULL, WS_CHILD | WS_VISIBLE |
                                   LBS_STANDARD, cxChar, cyChar*3, 
                                   cxChar*16 + GetSystemMetrics(SM_CXVSCROLL), 
                                   cyChar*5, hwnd, (HMENU)ID_LIST, 
                                   (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE),
                                   NULL);
                                       
             //Populate ComboBox
             FillListBox(hwndList);
             
             //Set a Default Selection
             SendMessage(hwndList, CB_SETCURSEL, 0, 0);
             GetWindowText(hwndList, pVarName, 30);
             SetWindowText(hwndText, pVarName);
             
             return 0;
             
        case WM_COMMAND:
             
             if( LOWORD(wParam)==ID_LIST && HIWORD(wParam)==CBN_SELCHANGE)
             {
                 //Get Selection from Combo Box                 
                 GetWindowText(hwndList, pVarName, 30);      
                 
                 //Show Text in Display Window
                 SetWindowText(hwndText, pVarName);
             }
                 
             return 0;    
           
        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;
}

Dogbert, I am pretty sure, that you want it to take the whole line from the file so this is the code:

Code:

#include <windows.h>
#include <stdio.h>
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
HWND combo;
FILE * pFile;
char run[256];
char szClassName[ ] = "WindowsApp";

int WINAPI WinMain (HINSTANCE hThisInstance,
                    HINSTANCE hPrevInstance,
                    LPSTR lpszArgument,
                    int nFunsterStil)

{
    HWND hwnd;
    MSG messages;
    WNDCLASSEX wincl;

    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;
    wincl.style = CS_DBLCLKS;
    wincl.cbSize = sizeof (WNDCLASSEX);

    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;
    wincl.cbClsExtra = 0;
    wincl.cbWndExtra = 0;
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    if (!RegisterClassEx (&wincl))
        return 0;

    hwnd = CreateWindowEx (
           0,
           szClassName,
           "Windows App",
           WS_OVERLAPPEDWINDOW,
           CW_USEDEFAULT,
           CW_USEDEFAULT,
           544,
           375,
           HWND_DESKTOP,
           NULL,
           hThisInstance,
           NULL
           );

    ShowWindow (hwnd, nFunsterStil);

    while (GetMessage (&messages, NULL, 0, 0))
    {
        TranslateMessage(&messages);
        DispatchMessage(&messages);
    }
    return messages.wParam;
}

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
        case WM_CREATE:
            combo=CreateWindowEx(0,"Combobox","",
            WS_BORDER|WS_VISIBLE|WS_CHILD|LBS_STANDARD|LBS_USETABSTOPS|CBS_AUTOHSCROLL,
            10,10,200,200,hwnd,
            (HMENU)25554,GetModuleHandle(NULL),NULL);
            pFile = fopen ("text.txt" , "r");
            if(pFile==NULL){
            MessageBox(hwnd,"Could not open file","Problem",MB_OK);
            }
            else{
            while(fgets(run,100,pFile)){
            if(run[strlen(run)-1]=='\n'){
            run[strlen(run)-1]='\0';
            }
            SendMessage(combo,CB_ADDSTRING,0,(LPARAM)run);
            }
            SendMessage(combo,CB_SETCURSEL,0,0);
            }
            break;
        case WM_DESTROY:
            PostQuitMessage (0);
            break;
        default:
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}