MFC SDI动态创建按钮

Question

我正在尝试动态创建一个按钮。我已经阅读了一些其他资源，并编写了以下代码：

BEGIN_MESSAGE_MAP(Cdynamic_button_sdiView, CView)
    // Standard printing commands
    ON_BN_CLICKED(MYBUTTONID, OnMyBN_Click)
END_MESSAGE_MAP()
void Cdynamic_button_sdiView::OnInitialUpdate()
{
    CView::OnInitialUpdate();
    m_Button.Create(_T("Rearrange"), WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, CRect(0, 0, 128, 32), this, MYBUTTONID); // here will create a button
}

当我启动MFC应用程序时，我可以成功地制作一个按钮。问题是，当我尝试通过单击打开新文档时：

我收到一个错误，我的应用程序在m_Button.Create(_T("Rearrange"), WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, CRect(0, 0, 128, 32), this, MYBUTTONID);崩溃了

​

Answer 1

我用下面的代码解决了这个问题：

Cdynamic_button_sdiView::Cdynamic_button_sdiView()
{
    // TODO: add construction code here
    m_Button = NULL;
}

Cdynamic_button_sdiView::~Cdynamic_button_sdiView()
{
    if (m_Button != NULL)
        delete m_Button;
}
void Cdynamic_button_sdiView::OnInitialUpdate()
{
    CView::OnInitialUpdate();

    if (m_Button != NULL)
        delete m_Button;

    m_Button = new CButton;
    m_Button->Create(_T("Rearrange"), WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, CRect(0, 0, 128, 32), this, MYBUTTONID); // here will create a button
}

问题可能是我不应该在OnInitialUpdate()中重新创建窗口