子窗口无法创建

Question

编辑：现在这很奇怪，如果我将对 jItems :: populate（std :: string myList）的调用移动到 jDropDown的构造函数： ：jDropDown 来自于 jDropDown :: jDropDown 中的其他位置，子窗口被创建。

最初在下拉（jDropDown）窗口可见（显示）时被调用，并且程序流程不允许调用 jItems :: populate（std :: string myList）被移动到 jDropDown :: jDropDown 的构造函数。

---

我想要做的是从头开始创建一个自定义Dropdown框，我面临的问题是没有创建最终的Items（jItem）窗口，它的oop设计和 每个Items（jItem）都是从jPanel派生的，下拉框的其他部分也是从jPanel驱动的，因此创建每个窗口都遵循相同的过程但最终 Items（jItem）窗口没有创建，它们不可见，我用Visual Studio Spy ++找不到它们

我检查了实例句柄和窗口句柄，两个检查都返回true，但是jItem窗口不可见，并且在spy ++中找不到它们（我可以在spy ++中看到所有其他窗口）

感谢任何帮助。

这是参考图像和一些相关代码。

bool jPanel::registered = false;


jPanel::jPanel( std::string txt, int x, int y, int width, int height, HWND parent, HINSTANCE hInstance, WORD bitmap, DWORD style ) 
                  : jControl( parent, hInstance, bitmap )
{


    if ( ! registered )
    {

        WNDCLASSEX wincl;

        wincl.hInstance         = hInstance;
        wincl.lpszClassName     = "jPanel";
        wincl.lpfnWndProc       = WndProc;
        wincl.style             = CS_BYTEALIGNWINDOW;
        wincl.cbSize            = sizeof ( WNDCLASSEX );
        wincl.hIcon             = 0;
        wincl.hIconSm           = 0;
        wincl.hCursor           = ::LoadCursor ( NULL, IDC_ARROW );
        wincl.lpszMenuName      = NULL;
        wincl.cbClsExtra        = 0;
        wincl.cbWndExtra        = 4;
        wincl.hbrBackground     = ::CreateSolidBrush ( backgroundColor );



        ::RegisterClassEx ( &wincl );


        jPanel::registered = true;

    }

    DWORD flag = WS_CLIPCHILDREN | WS_CLIPSIBLINGS | WS_CHILD;

    if ( style )    flag = flag | style;


    hwnd = ::CreateWindowEx ( 0, "jPanel", txt.c_str (  ), flag, x, y, width, height, parent, 0, hInstance, ( LPVOID ) this ) ;


};



jDropDown::jDropDown ( std::string txt, int x, int y, int width, int height, HWND parent, HINSTANCE hInstance, WORD bitmap )
                     : jPanel ( txt, x, y, width, height, parent, hInstance, bitmap ), capture ( false ), populated ( false )
{

    RECT rect;

    ::GetWindowRect ( hwnd, &rect );

    ::MapWindowPoints ( HWND_DESKTOP, ::GetParent ( parent ), ( LPPOINT ) &rect, 2 );


    items = new jItems ( "My Items List", rect.left, rect.top + height, width, 300, ::GetParent( parent ), hInstance, 0 );

    items->setBackgroundColor (  RGB ( 100, 100, 100 )  );

};




jItems::jItems ( std::string txt, int x, int y, int width, int height, HWND parent, HINSTANCE hInstance, WORD bitmap )
                     : jPanel ( txt, x, y, width, height, parent, hInstance, bitmap ), wWidth ( width ), wHeight ( 30 )
{

    ::SetWindowPos ( this->hwnd, HWND_TOP, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE );

};





bool jItems::populate ( std::string myList )
{



    int y = 0;
    Hinstance hInstance = ::GetModuleHandle ( NULL );


    std::vector < std::string >  list = model::Service::explode ( "^", myList );


    for (   std::vector < std::string >::const_iterator it = list.begin (  );       it != list.end (  );        ++it    )
    {

        std::string s = *it;


        jItem *i = new jItem ( "Your Item", 0, y, wWidth, wHeight, this->hwnd, hInstance, 0 );

    }


    ::SetWindowPos ( this->hwnd, HWND_TOP, 0, 0, wWidth, list.size (  ) * wHeight, SWP_NOMOVE | SWP_NOZORDER );


    return true;

};



jItem::jItem ( std::string txt, int x, int y, int width, int height, HWND parent, HINSTANCE hInstance, WORD bitmap )
                     : jPanel ( txt, x, y, width, height, parent, hInstance, bitmap ), empty ( false )
{



    this->setBackgroundColor (  RGB ( 65, 65, 65 )  );



};