我正在尝试组织一个 wxListCtrl 派生控件（ ），它支持项目（视图）xList之间的 DnD 。LC_REPORT所以，我抓住了 BEGIN_DRAG 事件
Connect(wxEVT_COMMAND_LIST_BEGIN_DRAG,
(wxObjectEventFunction)&xList::OnBeginDrag
);
和函数的设计方式是捕捉每个( )OnBeginDrag实例的鼠标运动和鼠标左键向上事件：xListlist
list->Connect(wxEVT_MOTION,
wxMouseEventHandler(xList::OnMoveDrag)
);
list->Connect(wxEVT_LEFT_UP,
wxMouseEventHandler(xList::OnEndDrag)
);
（并将OnEndDrag它们全部断开）。当我有单个xList实例（一个面板）时，它工作得很好，但是当我有两个时，它看起来像运动和左上事件仅针对我开始拖动的面板捕获：我可以在单个面板内 DnD，但是当我拖动鼠标时从一个面板到另一个面板，它仍然像xList::OnMoveDrag仍在为第一个面板工作。我想念什么？
是否wxEVT_MOTION为每个小部件分别处理？如果是这样，为什么程序会这样。如果不是，为什么总是为我开始拖动的小部件而不是最后一个连接的小部件处理它？
这是一个示例代码（尽可能简单）来显示正在发生的事情：
#include <wx/wx.h>
#include <vector>
class xList;
// class to store group of xList to DnD between
class DnDxList
{public:
void BeginDrag ();
void EndDrag ();
void AddList (xList* l) {list.push_back (l); }; // register new xList object
private:
std::vector<xList*> list;
};
class xList: public wxListCtrl
{public:
xList (DnDxList& dnd,
wxWindow *parent,
wxWindowID winid = wxID_ANY,
const wxPoint& pos = wxDefaultPosition,
const wxSize& size = wxDefaultSize,
long style = wxLC_ICON,
const wxValidator &validator = wxDefaultValidator,
const wxString &name = wxListCtrlNameStr
);
virtual ~xList () {};
void OnBeginDrag(wxListEvent& event);
void OnEndDrag(wxMouseEvent& event);
void OnMoveDrag(wxMouseEvent& event);
DnDxList& dndsource; // keep reference to common DnDxList object
};
void DnDxList::BeginDrag () // connect motion and left-up events for all lists in group
{for (std::vector<xList*>::const_iterator i = list.begin(); i != list.end(); i++)
{(*i)->Connect(wxEVT_MOTION,
wxMouseEventHandler(xList::OnMoveDrag)
);
(*i)->Connect(wxEVT_LEFT_UP,
wxMouseEventHandler(xList::OnEndDrag)
);
}
};
void DnDxList::EndDrag () // disconnect all
{for (std::vector<xList*>::const_iterator i = list.begin(); i != list.end(); i++)
{(*i)->Disconnect(wxEVT_MOTION,
wxMouseEventHandler(xList::OnMoveDrag)
);
(*i)->Disconnect(wxEVT_LEFT_UP,
wxMouseEventHandler(xList::OnEndDrag)
);
}
}
xList::xList (DnDxList& dnd,
wxWindow *parent,
wxWindowID winid,
const wxPoint& pos,
const wxSize& size,
long style,
const wxValidator &validator,
const wxString &name
): wxListCtrl (parent, winid, pos, size, style, validator, name),
dndsource (dnd)
{Connect(wxEVT_COMMAND_LIST_BEGIN_DRAG,
(wxObjectEventFunction)&xList::OnBeginDrag
);
dndsource.AddList (this);
};
void xList::OnBeginDrag(wxListEvent& event) // begin drag
{SetCursor(wxCursor(wxCURSOR_HAND));
dndsource.BeginDrag();
}
void xList::OnMoveDrag(wxMouseEvent& event)
{std::cout << "Movie: " << this << std::endl; // to show the object for which the move event is called for
}
void xList::OnEndDrag(wxMouseEvent& event)
{std::cout << "End: " << this << std::endl;
dndsource.EndDrag();
SetCursor(wxCursor(*wxSTANDARD_CURSOR));
}
class xFrame: public wxFrame
{
public:
xFrame (const wxString& title,
const wxPoint& pos,
const wxSize& size
);
~xFrame () { }
private:
void OnExit(wxCommandEvent& event);
DECLARE_EVENT_TABLE();
DnDxList* dndxlist;
xList* lp;
xList* rp;
wxPanel* panel;
};
BEGIN_EVENT_TABLE(xFrame, wxFrame)
EVT_MENU(wxID_EXIT, xFrame::OnExit)
END_EVENT_TABLE()
xFrame::xFrame(const wxString& title,
const wxPoint& pos,
const wxSize& size
): wxFrame(NULL, wxID_ANY, title, pos, size)
{
panel = new wxPanel(this);
wxBoxSizer* sizer = new wxBoxSizer(wxHORIZONTAL);
// create common DnDxList
dndxlist = new DnDxList();
// create two panels
lp = new xList (*dndxlist,
panel,
wxID_ANY,
wxDefaultPosition,
wxDefaultSize,
wxLC_REPORT | wxLC_SINGLE_SEL
);
rp = new xList (*dndxlist,
panel,
wxID_ANY,
wxDefaultPosition,
wxDefaultSize,
wxLC_REPORT | wxLC_SINGLE_SEL
);
// some contents
lp->InsertColumn(0, _("A"));
lp->InsertColumn(1, _("B"));
lp->InsertColumn(2, _("C"));
lp->InsertColumn(3, _("D"));
lp->SetColumnWidth(0, 100);
lp->SetColumnWidth(1, 100);
lp->SetColumnWidth(2, 100);
lp->SetColumnWidth(3, 100);
for (long i = 0; i < 100; i++)
{lp->InsertItem(i, 1);
for (int j = 0; j < 4; j++)
{wxString s;
s << _("lp [") << i << _(", ") << j << _("]");
lp->SetItem (i, j, s);
}
}
rp->InsertColumn(0, _("A"));
rp->InsertColumn(1, _("B"));
rp->InsertColumn(2, _("C"));
rp->InsertColumn(3, _("D"));
rp->SetColumnWidth(0, 100);
rp->SetColumnWidth(1, 100);
rp->SetColumnWidth(2, 100);
rp->SetColumnWidth(3, 100);
for (long i = 0; i < 100; i++)
{rp->InsertItem(i, 1);
for (int j = 0; j < 4; j++)
{wxString s;
s << _("rp [") << i << _(", ") << j << _("]");
rp->SetItem (i, j, s);
}
}
sizer->Add(lp,1, wxEXPAND | wxALL, 10);
sizer->Add(rp,1, wxEXPAND | wxALL, 10);
panel->SetSizer(sizer);
}
void xFrame::OnExit(wxCommandEvent& event)
{
Close( true );
}
class xApp: public wxApp
{
public:
virtual bool OnInit();
};
IMPLEMENT_APP(xApp);
bool xApp::OnInit()
{
xFrame *frame = new xFrame(_("Frame"), wxPoint(50, 50), wxSize(450, 340) );
frame->Show(true);
return true;
}
查看控制台输出可以发现鼠标移动事件和鼠标左上事件总是为同一个对象调用方法，拖动从哪里开始，而不是鼠标实际上是在对象上。