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Problems setting text. PLZZZ Help!

austinfarmer90 (5)
Ok, I have an int that I want to display in an edit control. I used stringstream to convert the int to a char, but when I compile it tells me that I can only use a const char. This simply will not work for me, because from what I understand of constants, they cannot change.

Is there a way to set text to a char or even a string variable? If not, is there a different type of edit control that I should be using?
kbw (9488)
It might be helpful if you posted the relevant code with the error.

You code should look something like:
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std::ostringstream os;
os << iValue;

std::string str = os.str();
control.SetWindowText(str.c_str());
austinfarmer90 (5)
Ok heres the code that I was trying to use NumFIN is the int, NumConverted is a char, and ss is the stringstream.

The error that I get is "invalid conversion from char to const char"

NumFIN = GetDlgItemInt(hwndTextbox, ID_TEXTBOX, NULL, NULL);
            ss <<NumFIN;
            ss >>NumConverted;
            Func();
            SetWindowText(hwndAnswerbox, NumConverted);
kbw (9488)
Can you show the declaration of NumConverted? We need to see the type.

And what line is the error referring to?
Last edited on
austinfarmer90 (5)
The error refers to line 148 the SetWindowText command. Heres the code I've been using hope this helps.



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#include <windows.h>
#include <sstream>
#include <string.h>

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

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

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

{
    HWND hwnd;               /* This is the handle for our window */
    HDC hdc;
    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 = GetSysColorBrush(COLOR_3DFACE);

    /* 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 */
           "AAF App",           /* Title Text */
           WS_SYSMENU,          /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           500,                 /* 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;
}
#define ID_BTN 1
#define ID_TEXTBOX 2
#define ID_TEXTBOX2 3
#define ID_TEXTBOX4 4

static HWND hwndTextbox;
static HWND hwndAnswerbox;
std::stringstream ss;
int NumFIN = 10;

void Func(){
       MessageBox(NULL, NumFIN+"", "Message Box", MB_OK);
       }



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

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{       
        int len = GetWindowTextLength(hwndTextbox) + 1;
        static char title[50];
      
        char NumConverted = 0;
        
        
switch (message)                  /* handle the messages */
    {
      case WM_CREATE:{
 
         hwndTextbox = CreateWindow(TEXT("EDIT"), TEXT(""),
             WS_VISIBLE | WS_CHILD | WS_BORDER | ES_NUMBER | ES_MULTILINE | WS_VSCROLL,
             10,50, 250, 265,
             hwnd, (HMENU) ID_TEXTBOX, NULL, NULL
              );
              
        hwndAnswerbox = CreateWindow(TEXT("EDIT"), TEXT(""),
             WS_VISIBLE | WS_CHILD | WS_BORDER | ES_READONLY | ES_CENTER | WS_VSCROLL | WS_HSCROLL | ES_MULTILINE,
             270, 100, 200, 215,
             hwnd, (HMENU) ID_TEXTBOX2, NULL, NULL
              );
              
         CreateWindow(TEXT("EDIT"), TEXT("Final Answer"),
             WS_VISIBLE | WS_CHILD | WS_BORDER | ES_READONLY | ES_CENTER,
             300, 50, 125, 25,
             hwnd, (HMENU) ID_TEXTBOX4, NULL, NULL
              );
              
              
         CreateWindow(TEXT("button"), TEXT("Compute"),
             WS_VISIBLE | WS_CHILD, 
             10, 10, 250, 30,
             hwnd, (HMENU) ID_BTN, NULL, NULL
              );
              
              break;
        
        } 
        
 case WM_COMMAND:{
      // this is pretty much a function that will handle
      // button events and 
        // Actions for default buttons
        if (LOWORD(wParam) == ID_BTN){
            //create default variables
            
            GetWindowText(hwndTextbox, title, len);
            // create the message box
            if (len > 0){        
           // NumFIN = GetDlgItemInt(hwndTextbox, ID_TEXTBOX, NULL, NULL);
            ss <<NumFIN;
            ss >>NumConverted;
            Func();
            //TextOut(hdc, 300, 5, NumConverted, len);
            SetWindowText(hwndAnswerbox, NumConverted+"");
           // MessageBox(hwnd, "Too Long", "Message Box", MB_OK);
            }else{
            MessageBox(hwnd, "Too Short", "Message Box", MB_OK);
            } 
                 
          }
            
        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;
}
kbw (9488)
Ok, it's a char. It should be string. Also, try to declare variables where they're used.

If you define it to be a string, you get:
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std::string NumConverted;
NumFIN = GetDlgItemInt(hwndTextbox, ID_TEXTBOX, NULL, NULL);
ss <<NumFIN;
ss >>NumConverted;
SetWindowText(hwndAnswerbox, NumConverted.c_str());


or if you opt for a char array for whatever reason:

char NumConverted[MAXLEN];
NumFIN = GetDlgItemInt(hwndTextbox, ID_TEXTBOX, NULL, NULL);
ss <<NumFIN;
ss >>NumConverted;
SetWindowText(hwndAnswerbox, NumConverted);


But you should use std::string for strings unless there's a reason to do otherwise.
andywestken (4087)
It yould be better if you used the approach kbw first suggested; using the str() method to obtain the string rather than the extraction operator. Then you can use an ostringstream rather than a stringstream; you can even do it without the string variable.

Also, there is no need for either ss or NumFin to be global. It would be better if they wer declared where they're needed.

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int NumFIN = GetDlgItemInt(hwndTextbox, ID_TEXTBOX, NULL, NULL);
std::ostringstream ss;
ss <<NumFIN;
SetWindowText(hwndAnswerbox, ss.str().c_str());


Andy

PS The broken function on line 84 would be better as

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// hWnd is the parent window's handle
void Func(HWND hWnd, int NumFIN){
    std::ostringstream ss;
    ss <<NumFIN;
    MessageBoxA(hWnd, ss.str().c_str(), "Message Box", MB_OK);
}
Last edited on
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