社区 › C++ › 请教回掉函数问题

yourwcd 发表于 2007-1-22 11:10:00

请教回掉函数问题

WNDPROC procOld;
LRESULT CALLBACK NewAcadWndProc(
HWND hwnd,      // handle to window
UINT uMsg,      // message identifier
WPARAM wParam,// first message parameter
LPARAM lParam   // second message parameter
);
class CmyToolbar2App : public AcRxArxApp {
public:
LRESULT CALLBACK NewAcadWndProc(HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
{
switch(iMsg)
{
case WM_MOUSEMOVE:
//lParam = MAKELPARAM(200,200);//禁止移动光标
break;
case WM_LBUTTONDOWN:
AfxMessageBox("WM_LBUTTONDOWN");//响应鼠标左键
break;
case WM_MOUSEWHEEL:
AfxMessageBox("WM_MOUSEWHEEL");//响应鼠标滚动
break;
default:
break;
}
return ::CallWindowProc(procOld, hwnd, iMsg, wParam, lParam);
}
CmyToolbar2App () : AcRxArxApp () {}
virtual AcRx::AppRetCode On_kInitAppMsg (void *pkt) {
AcRx::AppRetCode retCode =AcRxArxApp::On_kInitAppMsg (pkt) ;
procOld = (WNDPROC)::SetWindowLong(acedGetAcadDwgView()->GetSafeHwnd(),GWL_WNDPROC, (LONG)NewAcadWndProc);
   CAcModuleResourceOverride resOverride;
return (retCode) ;
}
} ;

这一行有错误：
procOld = (WNDPROC)::SetWindowLong(acedGetAcadDwgView()->GetSafeHwnd(),GWL_WNDPROC, (LONG)NewAcadWndProc);
   CAcModuleResourceOverride resOverride;
包错信息：
e:\二次开发\我的演示\myToolbar2\acrxEntryPoint.cpp(96) : error C2440: “类型转换” : 无法从“LRESULT (__stdcall CmyToolbar2App::* )(HWND,UINT,WPARAM,LPARAM)”转换为“LONG”
      转换是有效的标准转换，可以隐式执行或通过使用 static_cast、C 样式转换或函数样式转换执行
相似的回掉函数在MFC工程中却没有报错

yourwcd 发表于 2007-1-30 10:33:00

问题解决，代码如下：
WNDPROC procOld;
LRESULT CALLBACK NewAcadWndProc(
HWND hwnd,      // handle to window
UINT uMsg,      // message identifier
WPARAM wParam,// first message parameter
LPARAM lParam   // second message parameter
);
LRESULT CALLBACK NewAcadWndProc(HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
{
switch(iMsg)
{
case WM_MOUSEMOVE:
//lParam = MAKELPARAM(200,200);//禁止移动光标
break;
case WM_LBUTTONDOWN:
AfxMessageBox("WM_LBUTTONDOWN");//响应鼠标左键
break;
case WM_MOUSEWHEEL:
AfxMessageBox("WM_MOUSEWHEEL");//响应鼠标滚动
break;
default:
break;
}
return ::CallWindowProc(procOld, hwnd, iMsg, wParam, lParam);
}
class CmyToolbar2App : public AcRxArxApp {
public:
CmyToolbar2App () : AcRxArxApp () {}
virtual AcRx::AppRetCode On_kInitAppMsg (void *pkt) {
AcRx::AppRetCode retCode =AcRxArxApp::On_kInitAppMsg (pkt) ;
procOld = (WNDPROC)::SetWindowLong(acedGetAcadDwgView()->GetSafeHwnd(),GWL_WNDPROC, (LONG)NewAcadWndProc);
   CAcModuleResourceOverride resOverride;
return (retCode) ;
}
} ;

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