如图是一个简单的加法计算器：

方法一：

void CMy01_DemoDlg::OnBnClickedButton1()
{
	// TODO: 在此添加控件通知处理程序代码
	int num1, num2, num3;
	TCHAR ch1[12], ch2[12], ch3[12];

	GetDlgItem(IDC_EDIT1)->GetWindowText(ch1, 12);
	GetDlgItem(IDC_EDIT2)->GetWindowText(ch2, 12);

	num1 = _ttoi(ch1);
	num2 = _ttoi(ch2);
	num3 = num1 + num2;

	_itot(num3, ch3, 10);
	GetDlgItem(IDC_EDIT3)->SetWindowText(ch3);
}

方法二：

void CMy01_DemoDlg::OnBnClickedButton2()
{
	// TODO: 在此添加控件通知处理程序代码
	int num1, num2, num3;
	TCHAR ch1[12], ch2[12], ch3[12];

	GetDlgItemText(IDC_EDIT1, ch1, 12);
	GetDlgItemText(IDC_EDIT2, ch2, 12);

	num1 = _ttoi(ch1);
	num2 = _ttoi(ch2);
	num3 = num1 + num2;

	_itot(num3, ch3, 10);
	SetDlgItemText(IDC_EDIT3, ch3);
}

方法三：

void CMy01_DemoDlg::OnBnClickedButton3()
{
	// TODO: 在此添加控件通知处理程序代码
	int num1, num2, num3;
	num1 = GetDlgItemInt(IDC_EDIT1);
	num2 = GetDlgItemInt(IDC_EDIT2);
	num3 = num1 + num2;
	SetDlgItemInt(IDC_EDIT3, num3);
}

方法四和方法五是关联法，常用到的四个函数：

DoDataExchange();
DDC_xxxx();//关联变量
DDV_xxxx();//验证变量
UpdateData();//UpdateData(TRUE)为从编辑框获取数据，UpdateData(FALSE)为更新数据到编辑框

CMy01_DemoDlg::CMy01_DemoDlg(CWnd* pParent /*=NULL*/)
	: CDialogEx(IDD_MY01_DEMO_DIALOG, pParent)
	, m_num1(0)
	, m_num2(0)
	, m_num3(0)
{
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CMy01_DemoDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialogEx::DoDataExchange(pDX);
	DDX_Text(pDX, IDC_EDIT1, m_num1);
	DDX_Text(pDX, IDC_EDIT2, m_num2);
	DDX_Text(pDX, IDC_EDIT3, m_num3);
	DDX_Control(pDX, IDC_EDIT1, m_edit1);
	DDX_Control(pDX, IDC_EDIT2, m_edit2);
	DDX_Control(pDX, IDC_EDIT3, m_edit3);
}

方法四：

将编辑框与整形变量关联，然后对整形成员变量直接进行操作

void CMy01_DemoDlg::OnBnClickedButton4()
{
	// TODO: 在此添加控件通知处理程序代码
	UpdateData(true);
	m_num3 = m_num1 + m_num2;
	UpdateData(false);
}

方法五：

将编辑框与控件变量关联，对控件变量进行操作

void CMy01_DemoDlg::OnBnClickedButton5()
{
	// TODO: 在此添加控件通知处理程序代码
	int num1, num2, num3;
	TCHAR ch1[12], ch2[12], ch3[12];

	m_edit1.GetWindowText(ch1, 12);
	m_edit2.GetWindowText(ch2, 12);

	num1 = _ttoi(ch1);
	num2 = _ttoi(ch2);
	num3 = num1 + num2;

	_itot(num3, ch3, 10);
	m_edit3.SetWindowText(ch3);
}

方法六：

void CMy01_DemoDlg::OnBnClickedButton6()
{
	// TODO: 在此添加控件通知处理程序代码
	int num1, num2, num3;
	TCHAR ch1[12], ch2[12], ch3[12];

	::SendMessage(GetDlgItem(IDC_EDIT1)->m_hWnd, WM_GETTEXT, 12, (LPARAM)ch1);
	::SendMessage(GetDlgItem(IDC_EDIT2)->m_hWnd, WM_GETTEXT, 12, (LPARAM)ch2);

	num1 = _ttoi(ch1);
	num2 = _ttoi(ch2);
	num3 = num1 + num2;

	_itot(num3, ch3, 10);
	::SendMessage(GetDlgItem(IDC_EDIT3)->m_hWnd, WM_SETTEXT, 0, (LPARAM)ch3);
}

方法七：

void CMy01_DemoDlg::OnBnClickedButton7()
{
	// TODO: 在此添加控件通知处理程序代码
	int num1, num2, num3;
	TCHAR ch1[12], ch2[12], ch3[12];

	SendDlgItemMessage(IDC_EDIT1, WM_GETTEXT, 12, (LPARAM)ch1);
	SendDlgItemMessage(IDC_EDIT2, WM_GETTEXT, 12, (LPARAM)ch2);

	num1 = _ttoi(ch1);
	num2 = _ttoi(ch2);
	num3 = num1 + num2;
	_itot(num3, ch3, 10);

	SendDlgItemMessage(IDC_EDIT3, WM_SETTEXT, 0, (LPARAM)ch3);
}