首先要在焦点不在当前应用程序中也要获得鼠标位置，我们就需要使用全局鼠标钩子

我们先新建一个类库GlobalMouseHook，

然后导入命名空间：System.Windows.Forms;

System.Runtime.InteropServices;

将类重命名为MouseHook，其代码如下：

 

using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace GlobalMouseHook
{
    public class MouseHook
    {
        private const int WM_MOUSEMOVE = 0x200;
        private const int WM_LBUTTONDOWN = 0x201;
        private const int WM_RBUTTONDOWN = 0x204;
        private const int WM_MBUTTONDOWN = 0x207;
        private const int WM_LBUTTONUP = 0x202;
        private const int WM_RBUTTONUP = 0x205;
        private const int WM_MBUTTONUP = 0x208;
        private const int WM_LBUTTONDBLCLK = 0x203;
        private const int WM_RBUTTONDBLCLK = 0x206;
        private const int WM_MBUTTONDBLCLK = 0x209;

        //全局的事件
        public event MouseEventHandler OnMouseActivity;

        static int hMouseHook = 0; //鼠标钩子句柄

        //鼠标常量
        public const int WH_MOUSE_LL  = 14; //mouse hook constant

        HookProc MouseHookProcedure; //声明鼠标钩子事件类型.

        //声明一个Point的封送类型
        [StructLayout(LayoutKind.Sequential)]
        public class POINT
        {
            public int x;
            public int y;
        }

        //声明鼠标钩子的封送结构类型
        [StructLayout(LayoutKind.Sequential)]
        public class MouseHookStruct
        {
            public POINT pt;
            public int hWnd;
            public int wHitTestCode;
            public int dwExtraInfo;
        }

        //装置钩子的函数
        [DllImport("user32.dll",CharSet=CharSet.Auto, CallingConvention=CallingConvention.StdCall)]
        public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);

        //卸下钩子的函数
        [DllImport("user32.dll",CharSet=CharSet.Auto, CallingConvention=CallingConvention.StdCall)]
        public static extern bool UnhookWindowsHookEx(int idHook);

        //下一个钩挂的函数
        [DllImport("user32.dll",CharSet=CharSet.Auto, CallingConvention=CallingConvention.StdCall)]
        public static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam, IntPtr lParam);

        public delegate int HookProc(int nCode, Int32 wParam, IntPtr lParam);

        /// <summary>
        /// 墨认的构造函数构造当前类的实例.
        /// </summary>
        public MouseHook()
        {
        }

        //析构函数.
        ~MouseHook()
        {
        Stop();
        }

        public void Start()
        {
            //安装鼠标钩子
            if(hMouseHook == 0)
            {
                //生成一个HookProc的实例.
                MouseHookProcedure = new HookProc(MouseHookProc);

                hMouseHook = SetWindowsHookEx( WH_MOUSE_LL, MouseHookProcedure, Marshal.GetHINSTANCE(System.Reflection.Assembly.GetExecutingAssembly().GetModules()[0]), 0);

                //如果装置失败停止钩子
                if(hMouseHook == 0 )
                {
                    Stop();
                    throw new Exception("SetWindowsHookEx failed.");
                }
            }
        }

        public void Stop()
        {
            bool retMouse =true;
            if(hMouseHook != 0)
            {
                retMouse = UnhookWindowsHookEx(hMouseHook);
                hMouseHook = 0;
            }

            //如果卸下钩子失败
            if (!(retMouse)) throw new Exception("UnhookWindowsHookEx failed.");
        }

        private int MouseHookProc(int nCode, Int32 wParam, IntPtr lParam)
        {
            //如果正常运行并且用户要监听鼠标的消息
            if ((nCode >= 0) && (OnMouseActivity!=null))
            {
                MouseButtons button=MouseButtons.None;
                int clickCount=0;

                switch (wParam)
                {
                case WM_LBUTTONDOWN:
                button=MouseButtons.Left;
                clickCount=1;
                break;
                case WM_LBUTTONUP:
                button=MouseButtons.Left;
                clickCount=1;
                break;
                case WM_LBUTTONDBLCLK:
                button=MouseButtons.Left;
                clickCount=2;
                break;
                case WM_RBUTTONDOWN:
                button=MouseButtons.Right;
                clickCount=1;
                break;
                case WM_RBUTTONUP:
                button=MouseButtons.Right;
                clickCount=1;
                break;
                case WM_RBUTTONDBLCLK:
                button=MouseButtons.Right;
                clickCount=2;
                break;
            }

            //从回调函数中得到鼠标的信息
            MouseHookStruct MyMouseHookStruct = (MouseHookStruct) Marshal.PtrToStructure(lParam, typeof(MouseHookStruct));
            MouseEventArgs e=new MouseEventArgs(button, clickCount, MyMouseHookStruct.pt.x, MyMouseHookStruct.pt.y, 0 );
            //if(e.X>700)return 1;//如果想要限制鼠标在屏幕中的移动区域可以在此处设置
            OnMouseActivity(this, e);
        }
        return CallNextHookEx(hMouseHook, nCode, wParam, lParam);
        }
    }
}

 

这样就创建了一个全局的鼠标钩子，我们只需要在其它地方引用 这个dll就可以了

使用示例：

 

public partial class Form1 : Form
{
    MouseHook mouse = new MouseHook();
    public Form1()
    {
        InitializeComponent();
        mouse.OnMouseActivity += new MouseEventHandler(mouse_OnMouseActivity);
        mouse.Start();
    }

    void mouse_OnMouseActivity(object sender, MouseEventArgs e)
    {
        string str = "X:" + e.X + "  Y:" + e.Y;
        this.Text = str;
    }
}

 

这样这个窗体都可以在全局状态下显示鼠标的位置了，不管你焦点在哪，也不管你焦点是否在当前窗体上