如何在文本框包含浮点值时获取MFC中文本框的值

Question

I am doing a program in MFC and I have come up with an issue. I have a text box created by using the toolbars in Visual Studio.

My text box ID is IDC_TEXT1 and I need to get the value from the text box ( float value not string ). How do I do it?

Answer 1

You can get the value of by calling GetDlgItemText and std::stod like in this example:

class CAboutDlg : public CDialogEx
{
    CString m_txt;
    double m_num;
public:
    CAboutDlg() noexcept;

// Dialog Data
#ifdef AFX_DESIGN_TIME
    enum { IDD = IDD_ABOUTBOX };
#endif

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

// Implementation
protected:
    DECLARE_MESSAGE_MAP()
public:
    afx_msg void OnBnClickedOk();
};

CAboutDlg::CAboutDlg() noexcept : CDialogEx(IDD_ABOUTBOX)
{
}

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

BEGIN_MESSAGE_MAP(CAboutDlg, CDialogEx)
    ON_BN_CLICKED(IDOK, &CAboutDlg::OnBnClickedOk)
END_MESSAGE_MAP()

// App command to run the dialog
void CSO55114372App::OnAppAbout()
{
    CAboutDlg aboutDlg;
    aboutDlg.DoModal();
}

// CSO55114372App customization load/save methods

void CSO55114372App::PreLoadState()
{
    BOOL bNameValid;
    CString strName;
    bNameValid = strName.LoadString(IDS_EDIT_MENU);
    ASSERT(bNameValid);
    GetContextMenuManager()->AddMenu(strName, IDR_POPUP_EDIT);
    bNameValid = strName.LoadString(IDS_EXPLORER);
    ASSERT(bNameValid);
    GetContextMenuManager()->AddMenu(strName, IDR_POPUP_EXPLORER);
}

void CSO55114372App::LoadCustomState()
{
}

void CSO55114372App::SaveCustomState()
{
}

// CSO55114372App message handlers

void CAboutDlg::OnBnClickedOk()
{
    GetDlgItemText(IDC_EDIT2, m_txt);
    std::wstring s((LPCTSTR)m_txt);
    m_num = std::stod(s);
    CDialogEx::OnOK();
}

Answer 2

I just wanted to show you a second way of mapping a edit control to a float value. This is by using the ClassWizard .

• Right-click the control and choose Add Variable... :

• Set the variable category as value , the access to private , specify the name and finally set the variable type to float .

• Click Next (if required) and set the numeric range for input.

• Click Finish

---

Look at the DoDataExchange method. It will look something like this:

void CMFCApplication2Dlg::DoDataExchange(CDataExchange* pDX)
{
    CDialogEx::DoDataExchange(pDX);
    DDX_Text(pDX, IDC_EDIT1, m_fValue);
    DDV_MinMaxFloat(pDX, m_fValue, 1, 100);
}

Whenever you need to work with the current value of the edit control, you type UpdataData(TRUE); This synchronises the variable with the contents of the edit control . An example with a break-point in debug mode: