请问下Oncommnd消息和msg structure的区别

[a8326369]

MSG Structure是这么定义的
The MSG structure has the following form:

typedef struct tagMSG { // msg
HWND hwnd;
UINT message;
WPARAM wParam;
LPARAM lParam;
DWORD time;
POINT pt;
} MSG;
当我重载
BOOL CXXXXXDlg::PreTranslateMessage(MSG* pMsg)
{
if(pMsg->message == WM_LBUTTONDOWN)
{
if(pMsg->hwnd == ((CWnd*)GetDlgItem(IDC_BTDOME_01))->m_hWnd)
处理；
}}
可以根据Id来判断控件
但是这样为什么不行呢
BOOL CXXXXXDlg::PreTranslateMessage(MSG* pMsg)
{
if(pMsg->message == WM_LBUTTONDOWN)
{
if(LOWORD(pMsg->wparam) == IDC_BTDOME_01)
处理；
}}
用Oncommnd却可以根据wparam判断id

[gameslq]

>>用Oncommnd却可以根据wparam判断id
在Oncommnd 处理函数要晚于WM_LBUTTONDOWN消息，是系统处理之后，再传递id值给oncommnd
在WM_LBUTTONDOWN消息处理只有虚拟码，详细可参考msdn关于两个消息的说明

[wltg2001]

不能一回事，WM_COMMAND是由控件发给父窗体的，wParam参数记录了控件的ID。而WM_LBUTTONDOWN消息的wParam参数保存的并不是ID。

[Eleven]

WM_LBUTTONDOWN

WPARAM wParam
LPARAM lParam;

Parameters

wParam
Indicates whether various virtual keys are down. This parameter can be one or more of the following values.
MK_CONTROL
The CTRL key is down.
MK_LBUTTON
The left mouse button is down.
MK_MBUTTON
The middle mouse button is down.
MK_RBUTTON
The right mouse button is down.
MK_SHIFT
The SHIFT key is down.
MK_XBUTTON1
Windows 2000/XP: The first X button is down.
MK_XBUTTON2
Windows 2000/XP: The second X button is down.
lParam
The low-order word specifies the x-coordinate of the cursor. The coordinate is relative to the upper-left corner of the client area.

The high-order word specifies the y-coordinate of the cursor. The coordinate is relative to the upper-left corner of the client area.

[jixiang1983]

wParam、lParam是消息的附加参数，不同类型的消息wParam、lParam的意义是不同的，WM_LBUTTONDOWN是标准消息，wParam的意义并非控件的ID，只有控件产生的通告消息（WM_COMMAND）的附加参数wParam（低位）是控件的ID