为全局鼠标钩创建新的MouseWheelEventArgs

Question

As per MSDN below is the MouseWheelEventArgs constructor

public MouseWheelEventArgs(
    MouseDevice mouse,
    int timestamp,
    int delta
)

This is a method from my Global Mouse Hook that I am trying to complete:

private static IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
{
    if (nCode >= 0 && MouseMessages.WM_MOUSEWHEEL == (MouseMessages)wParam)
    {
        MouseDevice mouseDev = InputManager.Current.PrimaryMouseDevice;

        MSLLHOOKSTRUCT hookStruct = (MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(MSLLHOOKSTRUCT));

        //Initializes a new instance of the MouseWheelEventArgs class using the specified MouseDevice, timestamp, and delta.
        MouseAction(null, new MouseWheelEventArgs(mouseDev, timestamp, delta));
    }
    return CallNextHookEx(_hookID, nCode, wParam, lParam);
}

What I'm looking for is:

Timestamp - it is fine to just generate current date time on the fly?

delta - you must be able to programmatically get this from the mouse device somehow, but how?

Answer 1

The Reference Source can show you that the timestamp is retrieved from "Environment.TickCount`.

The MSDN Library article for MSLLHOOKSTRUCT can show you that the delta is passed as the upper word of the MSLLHOOKSTRUCT.mouseData element. Make sure that you declared that member as int , not as uint , so that sign extension works properly.

Thus:

   int timestamp = Environment.TickCount;
   int delta = hookStruct.mouseData >> 16;
   MouseAction(null, new MouseWheelEventArgs(mouseDev, timestamp, delta));