Why do my radio buttons not work?

Question

I'm working on an MFC dialog application in Visual C++ 2005. My radio buttons are m_Small, m_Medium, and m_Large. None of them display what they are supposed to in my m_Summary edit box. What could be wrong?

Here's my code.

    // Pizza_ProgramDlg.cpp : implementation file
//

#include "stdafx.h"
#include "Pizza_Program.h"
#include "Pizza_ProgramDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif


// CAboutDlg dialog used for App About

class CAboutDlg : public CDialog
{
public:
    CAboutDlg();

// Dialog Data
    enum { IDD = IDD_ABOUTBOX };

    protected:
    virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV support

// Implementation
protected:
    DECLARE_MESSAGE_MAP()
};

CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{
}

void CAboutDlg::DoDataExchange(CDataExchange* pDX)
{
    CDialog::DoDataExchange(pDX);
}

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
END_MESSAGE_MAP()


// CPizza_ProgramDlg dialog




CPizza_ProgramDlg::CPizza_ProgramDlg(CWnd* pParent /*=NULL*/)
    : CDialog(CPizza_ProgramDlg::IDD, pParent)
    , m_Name(_T(""))
    , m_Address(_T(""))
    , m_Phone(_T(""))
    , m_Summary(_T(""))
    , m_Extra(FALSE)
    , m_Pepperoni(FALSE)
    , m_Sausage(FALSE)
    , m_Peppers(FALSE)
    , m_Mushrooms(FALSE)
    , m_Onions(FALSE)
    , m_Eatin(0)
    , m_Medium(0)
    , m_Large(0)
    , m_Takeout(0)
    , m_Delivery(0)
    , m_Small(0)
{
    m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CPizza_ProgramDlg::DoDataExchange(CDataExchange* pDX)
{
    CDialog::DoDataExchange(pDX);
    DDX_Text(pDX, IDC_EDIT_NAME, m_Name);
    DDV_MaxChars(pDX, m_Name, 1000);
    DDX_Text(pDX, IDC_EDIT_ADDRESS, m_Address);
    DDV_MaxChars(pDX, m_Address, 1000);
    DDX_Text(pDX, IDC_EDIT_PHONE, m_Phone);
    DDV_MaxChars(pDX, m_Phone, 1000);
    DDX_Text(pDX, IDC_EDIT_SUMMARY, m_Summary);
    DDV_MaxChars(pDX, m_Summary, 1000);
    DDX_Check(pDX, IDC_CHECK_EXTRA, m_Extra);
    DDX_Check(pDX, IDC_CHECK_PEPPERONI, m_Pepperoni);
    DDX_Check(pDX, IDC_CHECK_SAUSAGE, m_Sausage);
    DDX_Check(pDX, IDC_CHECK_PEPPERS, m_Peppers);
    DDX_Check(pDX, IDC_CHECK_MUSHROOMS, m_Mushrooms);
    DDX_Check(pDX, IDC_CHECK_ONIONS, m_Onions);
}

BEGIN_MESSAGE_MAP(CPizza_ProgramDlg, CDialog)
    ON_WM_SYSCOMMAND()
    ON_WM_PAINT()
    ON_WM_QUERYDRAGICON()
    //}}AFX_MSG_MAP
    ON_EN_CHANGE(IDC_EDIT_SUMMARY, &CPizza_ProgramDlg::OnEnChangeEditSummary)
    ON_BN_CLICKED(IDOK, &CPizza_ProgramDlg::OnBnClickedOk)
    ON_BN_CLICKED(IDC_BUTTON_PROCESS, &CPizza_ProgramDlg::OnBnClickedButtonProcess)
END_MESSAGE_MAP()


// CPizza_ProgramDlg message handlers

BOOL CPizza_ProgramDlg::OnInitDialog()
{
    CDialog::OnInitDialog();

    // Add "About..." menu item to system menu.

    // IDM_ABOUTBOX must be in the system command range.
    ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
    ASSERT(IDM_ABOUTBOX < 0xF000);

    CMenu* pSysMenu = GetSystemMenu(FALSE);
    if (pSysMenu != NULL)
    {
        CString strAboutMenu;
        strAboutMenu.LoadString(IDS_ABOUTBOX);
        if (!strAboutMenu.IsEmpty())
        {
            pSysMenu->AppendMenu(MF_SEPARATOR);
            pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
        }
    }

    // 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;  // return TRUE  unless you set the focus to a control
}

void CPizza_ProgramDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
    if ((nID & 0xFFF0) == IDM_ABOUTBOX)
    {
        CAboutDlg dlgAbout;
        dlgAbout.DoModal();
    }
    else
    {
        CDialog::OnSysCommand(nID, lParam);
    }
}

// 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 CPizza_ProgramDlg::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
    {
        CDialog::OnPaint();
    }
}

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


void CPizza_ProgramDlg::OnEnChangeEditSummary()
{

    // TODO:  If this is a RICHEDIT control, the control will not
    // send this notification unless you override the CDialog::OnInitDialog()
    // function and call CRichEditCtrl().SetEventMask()
    // with the ENM_CHANGE flag ORed into the mask.

    // TODO:  Add your control notification handler code here
}

void CPizza_ProgramDlg::OnBnClickedOk()
{
    // TODO: Add your control notification handler code here
    OnOK();
}

void CPizza_ProgramDlg::OnBnClickedButtonProcess()
{
    // TODO: Add your control notification handler code here

    UpdateData(TRUE);
    m_Summary += "Customer's Name: ";
    m_Summary += m_Name;
    m_Summary += char(13);
    m_Summary += char(10);
    m_Summary += "Customer's Address: ";
    m_Summary += m_Address;
    m_Summary += char(13);
    m_Summary += char(10);
    m_Summary += "Customer's Phone Number: ";
    m_Summary += m_Phone;


   if (m_Small==TRUE)
{
    m_Summary += char(13);
    m_Summary += char(10);
    m_Summary += "Small Pizza $5.00";
}
   else if (m_Medium==TRUE)
{
    m_Summary += char(13);
    m_Summary += char(10);
    m_Summary += "Medium Pizza $10.00";
}
   else if (m_Large==TRUE)
   { 
       m_Summary += char(13);
       m_Summary += char(10);
       m_Summary += "Large Pizza $15.00";
   }

   if (m_Extra==TRUE)
   {
       m_Summary += char(13);
       m_Summary += char(10);
       m_Summary += "Extra Cheese +$1.00";
   }

      if (m_Pepperoni==TRUE)
   {
       m_Summary += char(13);
       m_Summary += char(10);
       m_Summary += "Pepperoni +$1.00";
   }

         if (m_Sausage==TRUE)
   {
       m_Summary += char(13);
       m_Summary += char(10);
       m_Summary += "Sausage +$1.00";
   }

        if (m_Peppers==TRUE)
   {
       m_Summary += char(13);
       m_Summary += char(10);
       m_Summary += "Peppers +$1.00";
   }

           if (m_Mushrooms==TRUE)
   {
       m_Summary += char(13);
       m_Summary += char(10);
       m_Summary += "Mushrooms +$1.00";
   }
              if (m_Onions==TRUE)
   {
       m_Summary += char(13);
       m_Summary += char(10);
       m_Summary += "Onions +$1.00";
   }

    UpdateData(FALSE);
}

Answer 1

ChrisF's answer is excellent, the right way to do radio buttons in MFC.

One very important note: be sure that the radio buttons are sequentially in the dialog tab order as in the enum.

Answer 2

You need to add a call to DDX_Radio in your class's DoDataExchange function.

For this to work you should replace your m_Small, m_Medium, and m_Large member variables with a single integer:

int m_Size;

Assuming the ID of the first radio button is IDC_SMALL, then the DDX_Radio call would be:

DDX_Radio(pDX, IDC_SMALL, m_Size);

(Unfortunately, you can't declare m_Size as an enum because DDX_Radio expects an int.)

Also, as Aiden Ryan correctly points out, in the Visual Studio resource editor ensure that the radio buttons appear sequentially in the dialog tab order. The first radio button should have the Group property set to True and the other radio buttons should have the Group property set to False.

Answer 3

Radio buttons tend to be used for variables that have more that two values, so rather than having three variables:

BOOL m_Small;
BOOL m_Medium;
BOOL m_Large;

You'd have an enum:

enum PizzaSize {Small, Medium, Large};

and a variable of this type:

PizzaSize m_Size;

The radio buttons would set this variable.

Your code would then become:

switch (m_Size)
{
    case Small:
        m_Summary += char(13);
        m_Summary += char(10);
        m_Summary += "Small Pizza $5.00";
        break;
    case Medium:
        m_Summary += char(13);
        m_Summary += char(10);
        m_Summary += "Medium Pizza $10.00";
    case Large:
        m_Summary += char(13);
        m_Summary += char(10);
        m_Summary += "Large Pizza $15.00";
}

It's a while since I've done C++ & MFC so treat this as a starting point rather than the definitive code ;)