Windows7を便利にしたい1

MouseUnderScroll.cs

using System;
using System.Runtime.InteropServices;

namespace MouseUnderScroll
{
	// Win32API
	public class WinAPI
	{
		[StructLayout(LayoutKind.Sequential)]
		public struct POINT
		{
			public int x;
			public int y;
		}

		[StructLayout(LayoutKind.Sequential)]
		public struct MouseLowLevelHookStruct
		{
			public POINT pt;
			public int mouseData;
			public int flags;
			public int time;
			public int dwExtraInfo;
		}

		public delegate int HookProc(int nCode, IntPtr wParam, IntPtr lParam);

		[DllImport("user32.dll")]
		public static extern IntPtr WindowFromPoint(POINT point);

		[DllImport("user32.dll")]
		public static extern int SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

		[DllImport("user32.dll")]
		public static extern IntPtr DefWindowProc(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

		[DllImport("user32.dll")]
		public static extern IntPtr SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);

		[DllImport("user32.dll")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool UnhookWindowsHookEx(IntPtr hHook);

		[DllImport("user32.dll")]
		public static extern int CallNextHookEx(IntPtr hHook, int nCode, IntPtr wParam, IntPtr lParam);

		[DllImport("kernel32.dll")]
		public static extern IntPtr GetModuleHandle(string lpModuleName);

		// フックコードに関する定数
		public const int HC_ACTION = 0;

		// ウィンドウズフックの定数
		public const int WH_MOUSE_LL = 14;

		// ウィンドウメッセージの定数
		public const int WM_MOUSEWHEEL = 0x020A;
	}

	public class MouseHook
	{
		private IntPtr _hHook = IntPtr.Zero;
		private WinAPI.HookProc _mouseHookProcedure = null;

		// コンストラクタ
		public MouseHook()
		{
			_mouseHookProcedure = new WinAPI.HookProc(LowLevelMouseHookProc);
			_hHook = WinAPI.SetWindowsHookEx(WinAPI.WH_MOUSE_LL, _mouseHookProcedure, WinAPI.GetModuleHandle(null), 0);
		}

		// デストラクタ
		~MouseHook()
		{
			WinAPI.UnhookWindowsHookEx(_hHook);
		}

		// マウス入力のフックプロシージャ
		private int LowLevelMouseHookProc(int nCode, IntPtr wParam, IntPtr lParam)
		{
			if( nCode == WinAPI.HC_ACTION ) {
				if( (int)wParam == WinAPI.WM_MOUSEWHEEL ) {
					WinAPI.MouseLowLevelHookStruct MyMouseHookStruct = (WinAPI.MouseLowLevelHookStruct)Marshal.PtrToStructure(lParam, typeof(WinAPI.MouseLowLevelHookStruct));
					SendMouseWheelMessage(WinAPI.WindowFromPoint(MyMouseHookStruct.pt), MyMouseHookStruct.pt, MyMouseHookStruct.mouseData);
				}
			}
			return WinAPI.CallNextHookEx(_hHook, nCode, wParam, lParam);
		}

		// マウスホイール操作のメッセージをウィンドウに送信
		private void SendMouseWheelMessage(IntPtr hWnd, WinAPI.POINT point, int mouseData)
		{
			uint mousePos = U16to32((uint)point.x, (uint)point.y);
			WinAPI.SendMessage(hWnd, WinAPI.WM_MOUSEWHEEL, (IntPtr)mouseData, (IntPtr)mousePos);
		}

		// 2つの16bitを1つの32bitにする
		private uint U16to32(uint lo, uint hi)
		{
			uint result = 0;

			result += (lo & 0xffff);
			result += (hi & 0xffff) << 16;

			return result;
		}
	}
}