原文地址:http://www.zdexe.com/program/201004/605.html
结构9：MSLLHOOKSTRUCT Structure
The MSLLHOOKSTRUCT structure contains information about a low-level keyboard input event. （msdn错误）
该MSLLHOOKSTRUCT结构包含有低层键盘输入事件的信息。
Syntax语法
typedef struct {
POINT pt;
DWORD mouseData;
DWORD flags;
DWORD time;
ULONG_PTR dwExtraInfo;
} MSLLHOOKSTRUCT, *PMSLLHOOKSTRUCT;
Members成员
pt ：Specifies a POINT structure that contains the x- and y-coordinates of the cursor, in screen coordinates. 指定在屏幕坐标系下，包含有光标x、y坐标的POINT结构。
mouseData
If the message is WM_MOUSEWHEEL, the HIWORD of this member is the wheel delta. The LOWORD is undefined and reserved. A positive value indicates that the wheel was rotated forward, away from the user; a negative value indicates that the wheel was rotated backward, toward the user. One wheel click is defined as WHEEL_DELTA, which is 120.
如果消息是WM_MOUSEWHEEL，该成员的HIWORD就是wheel delta。LOWORD做为保留未定义。正值表示滚轮向前旋转，即远离用户的方向；负值表示滚轮向后旋转，即朝向用户的方向。滚轮的点击被定义为WHEEL_DELTA,具体值为120。
If the message is WM_XBUTTONDOWN, WM_XBUTTONUP, WM_XBUTTONDBLCLK, WM_NCXBUTTONDOWN, WM_NCXBUTTONUP, or WM_NCXBUTTONDBLCLK, the HIWORD ofmouseData specifies which X button was pressed or released, and the LOWORD is undefined and reserved. This member can be one or more of the following values. Otherwise, mouseDatais not used.
如果消息是WM_XBUTTONDOWN, WM_XBUTTONUP, WM_XBUTTONDBLCLK, WM_NCXBUTTONDOWN, WM_NCXBUTTONUP, 或者 WM_NCXBUTTONDBLCLK, mouseData 的HIWORD值指定哪个X键被按下或者释放，LOWORD做为保留未定义。该成员可以是以下值中的一个或者多个。否则，mouseData未使用。
1．XBUTTON1：The first X button was pressed or released. 第一个X键被按下或者释放。
2．XBUTTON2 ：The second X button was pressed or released.第二个X键被按下或者释放。
flags
Specifies the event-injected flag. An application can use the following value to test the mouse flags. 指定事件注入标志。应用程序可以使用下列值来测试鼠标标志。
|
Value |
Purpose |
|
LLMHF_INJECTED |
Test the event-injected flag.测试事件注入标志。 |
0 : Specifies whether the event was injected. The value is 1 if the event was injected; otherwise, it is 0.
事件是否被注入。如果被注入，为 1，否则为0
1-15 ：Reserved.
保留
time : Specifies the time stamp for this message. 消息的时间戳。
dwExtraInfo : Specifies extra information associated with the message. 消息的扩展信息。