MFC CString: double not displaying

Question

I have two variables, m_GridSize and m_TimeDisplay, which update themselves according to a variable called "world" here. Now, the MFC program will display the words "Grid size: " and "Time: ", but it will not display the actual values of the doubles. I am using Visual Studio Community 2013 to make a Win32 GUI application.

I am having trouble with the CString Format function.

EDIT to include full code:

// smart_parking_guiDlg.cpp : implementation file
//

#include "stdafx.h"
#include "smart_parking_gui.h"
#include "smart_parking_guiDlg.h"
#include "afxdialogex.h"
#include "Cadd_Destination.h"
#include "Cadd_Lot.h"
#include "Cadd_Driver.h"
#include "Commands.h" // Used to handle commands
#include "Grid.h" // Contains the grid
#include <string>
#include <io.h>
#include <fcntl.h>

#ifdef _DEBUG
#define new DEBUG_NEW
#endif


// Csmart_parking_guiDlg dialog



Csmart_parking_guiDlg::Csmart_parking_guiDlg(CWnd* pParent /*=NULL*/)
    : CDialogEx(Csmart_parking_guiDlg::IDD, pParent)
    , m_EchoSize(_T("Grid size: "))
    , m_EchoTime(_T("Time: "))
    , m_EchoStatus(_T("Open"))
{
    m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
        this->world = new Grid(10, 5); // default grid
}

void Csmart_parking_guiDlg::DoDataExchange(CDataExchange* pDX)
{
    CDialogEx::DoDataExchange(pDX);
    DDX_Text(pDX, IDC_ST_GRIDSIZE, m_EchoSize);
    DDX_Text(pDX, IDC_ST_TIME, m_EchoTime);
    DDX_Text(pDX, IDC_ST_STATUS, m_EchoStatus);
}

BEGIN_MESSAGE_MAP(Csmart_parking_guiDlg, CDialogEx)
    ON_WM_PAINT()
    ON_WM_QUERYDRAGICON()
    ON_BN_CLICKED(IDC_B_OPEN_CONFIG, &Csmart_parking_guiDlg::OnBnClickedBOpenConfig)
    ON_BN_CLICKED(IDC_B_SAVECONFIG, &Csmart_parking_guiDlg::OnBnClickedBSaveconfig)
    ON_BN_CLICKED(IDC_B_NEXTEVENT, &Csmart_parking_guiDlg::OnBnClickedBNextevent)
    ON_BN_CLICKED(IDC_B_NEWDEST, &Csmart_parking_guiDlg::OnBnClickedBNewdest)
    ON_BN_CLICKED(IDC_B_NEWLOT, &Csmart_parking_guiDlg::OnBnClickedBNewlot)
    ON_BN_CLICKED(IDC_B_NEWDRIVER, &Csmart_parking_guiDlg::OnBnClickedBNewdriver)
    ON_BN_CLICKED(IDC_B_SIMEND, &Csmart_parking_guiDlg::OnBnClickedBSimend)
    ON_BN_CLICKED(IDC_B_SHOWSTATUS, &Csmart_parking_guiDlg::OnBnClickedBShowstatus)
END_MESSAGE_MAP()


// Csmart_parking_guiDlg message handlers

BOOL Csmart_parking_guiDlg::OnInitDialog()
{
    CDialogEx::OnInitDialog();

    // Set the icon for this dialog.  The framework does this automatically
    //  when the application's main window is not a dialog
    SetIcon(m_hIcon, TRUE);         // Set big icon
    SetIcon(m_hIcon, FALSE);        // Set small icon

    // TODO: Add extra initialization here

    return TRUE;
}

// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void Csmart_parking_guiDlg::OnPaint()
{
    if (IsIconic())
    {
        CPaintDC dc(this); // device context for painting

        SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);

        // Center icon in client rectangle
        int cxIcon = GetSystemMetrics(SM_CXICON);
        int cyIcon = GetSystemMetrics(SM_CYICON);
        CRect rect;
        GetClientRect(&rect);
        int x = (rect.Width() - cxIcon + 1) / 2;
        int y = (rect.Height() - cyIcon + 1) / 2;

        // Draw the icon
        dc.DrawIcon(x, y, m_hIcon);
    }
    else
    {
        CDialogEx::OnPaint();
    }
}

// The system calls this function to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR Csmart_parking_guiDlg::OnQueryDragIcon()
{
    return static_cast<HCURSOR>(m_hIcon);
}



void Csmart_parking_guiDlg::OnBnClickedBOpenConfig()
{
    wchar_t szFilters[] = _T("Text Files (*.txt)|*.txt|All Files (*.*)|*.*||");
    // Create an Open dialog
    CFileDialog fileDlg(TRUE, _T("txt"), _T("*.txt"),
        OFN_FILEMUSTEXIST | OFN_HIDEREADONLY, szFilters, this); // Display the file dialog. 

    // When user clicks OK, fileDlg.DoModal() returns IDOK.
    if (fileDlg.DoModal() == IDOK)
    {
        CString m_strPathname = fileDlg.GetPathName();
        CT2CA converter(m_strPathname);
        std::string fileToOpen(converter);
        // TODO: Open Grid file
        open_file(*world, fileToOpen);
        //Change the window's title to the opened file's title.
        CString fileName = fileDlg.GetFileTitle();

        SetWindowText(fileName);
    }
}


void Csmart_parking_guiDlg::OnBnClickedBSaveconfig()
{
    // TODO: Add your control notification handler code here
    // szFilters is a text string that includes two file name filters:
    // "*.my" for "MyType Files" and "*.*' for "All Files."
    TCHAR szFilters[] = _T("Text Files (*.txt)|*.txt|All Files (*.*)|*.*||");

    // Create a Save dialog
    CFileDialog fileDlg(FALSE, _T("txt"), _T("*.txt"),
        OFN_FILEMUSTEXIST | OFN_HIDEREADONLY, szFilters);

    // Display the file dialog. When user clicks OK, fileDlg.DoModal() 
    // returns IDOK.
    if (fileDlg.DoModal() == IDOK)
    {
        CString pathName = fileDlg.GetPathName();
        CT2CA converter(pathName);
        std::string fileToWrite(converter);
        // Implement opening and reading file in here.
        write_file(*world, fileToWrite);
        //Change the window's title to the opened file's title.
        CString fileName = fileDlg.GetFileTitle();

        SetWindowText(fileName);
    }
}


void Csmart_parking_guiDlg::OnBnClickedBNextevent()
{
    // TODO: Add your control notification handler code here
    run_simulation(*world);
    m_GridSize = world->getGridSize(); // double
    m_TimeDisplay = world->getTime(); // double
    // THIS DOESN'T WORK
    m_EchoSize.Format(_T("Grid size: %g"), m_GridSize);
    m_EchoTime.Format(_T("Time: %g"), m_TimeDisplay);
    UpdateData(FALSE);
    GetDlgItem(IDC_ST_GRIDSIZE)->InvalidateRect(NULL);
    GetDlgItem(IDC_ST_TIME)->InvalidateRect(NULL); 
}

void Csmart_parking_guiDlg::OnBnClickedBSimend() // On clicking, simulation jumps to the very end.
{
    jump_to_end(*world);
    m_GridSize = world->getGridSize();
    m_TimeDisplay = world->getTime();
    // THIS DOESN'T WORK
    m_EchoSize.Format(_T("Grid size: %g"), m_GridSize);
    m_EchoTime.Format(_T("Time: %g"), m_TimeDisplay);
    UpdateData(FALSE);
    GetDlgItem(IDC_ST_GRIDSIZE)->InvalidateRect(NULL);
    GetDlgItem(IDC_ST_TIME)->InvalidateRect(NULL);
}

void Csmart_parking_guiDlg::OnBnClickedBNewdest()
{
    // TODO: Add your control notification handler code here
    Cadd_Destination Dlg;
    Dlg.DoModal();
}


void Csmart_parking_guiDlg::OnBnClickedBNewlot()
{
    // TODO: Add your control notification handler code here
    Cadd_Lot Dlg;
    Dlg.DoModal();
}


void Csmart_parking_guiDlg::OnBnClickedBNewdriver() // Opens a dialog to input a new driver. Only works with added destination.
{
    if (world->getDestinationCount() != 0) {
        Cadd_Driver Dlg;
        Dlg.DoModal();
    }
}

void Csmart_parking_guiDlg::OnBnClickedBShowstatus()
{
    // TODO: Add your control notification handler code here

}

Is there any way to fix this in order to make the values of the doubles show up in the GUI? I have tried the answer shown here

C++ MFC double to CString

but the numbers do not show up at all. There are no syntax errors. The code works if I use %d and replace the values with integers, but it doesn't work with double values, which is what I used in my initial classes.

Answer 1

I have fixed the problem myself.

As it turns out, the issue had more to do with my GUI. It turns out that the Static Text has a set length set in the Visual Studio Dialog Editor (accessed through the Resource View) and the length was too short to hold both the string containing "Grid size:" and the actual numbers. (The first Static Text initially could only hold one digit for both of them) I fixed it by extending the width of the Static Text in my GUI, and that fixed the problem.

Answer 2

As implied by the name, Static text controls are not expected to change once they are created. They don't automatically repaint when you change their content with SetWindowText , which is what DDX_Text calls to set the new text. You need to inform Windows that the contents have changed and the control needs repainting:

GetDlgItem(IDC_ST_GRIDSIZE)->InvalidateRect(NULL);