我正在尝试组织一个wxListCtrl派生的控件（xList），它支持项目之间的DnD（LC_REPORT视图）。所以，我抓住了BEGIN_DRAG事件
Connect(wxEVT_COMMAND_LIST_BEGIN_DRAG,
(wxObjectEventFunction)&xList::OnBeginDrag
);
和OnBeginDrag函数的设计方式是为xList（list）的每个实例捕捉鼠标移动和鼠标左按钮事件：
list->Connect(wxEVT_MOTION,
wxMouseEventHandler(xList::OnMoveDrag)
);
list->Connect(wxEVT_LEFT_UP,
wxMouseEventHandler(xList::OnEndDrag)
);
（和OnEndDrag将它们全部断开连接）。当我有单xList个实例（一个面板）时，它可以很好地工作，但是当我有两个时，看起来像运动和左上方事件只捕获我开始拖动的面板：我可以DnD在单个面板内，但是当我将鼠标从一个面板拖动到另一个面板时，它仍然像xList::OnMoveDrag一样仍然适用于第一个面板。我错过了什么？
是否分别为每个小部件处理wxEVT_MOTION？如果是这样，为什么程序会像这样。如果没有，为什么总是处理小部件我开始拖动，而不是最后连接的？
这是一个示例代码（尽可能简单），以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移事件始终调用同一对象的方法，其中拖动开始，而不是对象鼠标实际上是。
答案 0 :(得分：0)
wxListCtrl - 特定的拖动事件确实只是用于拖动同一控件中的项目。要在不同控件之间拖放内容，甚至在不同应用程序之间拖放，您需要使用常规wxDragSource和wxDropTarget类。