C# WINFORM 使用鼠标钩子实现透明窗体桌面画图

来源：互联网发布：淘宝怎么看追评编辑：程序博客网时间：2024/04/29 17:33

接上次关于在C# WINFORM下制作透明窗体在系统桌面上画图方案是通过两个透明窗体实现的，现在讨论一下使用API底层鼠标钩子+透明窗体实现方法，这种实现方法比效麻烦，需要重新监听实现鼠标操作，在这儿只做交流学习，功能还待完善，直接上代码：

创建一个透明窗体Form1；

Form1.cs代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Diagnostics;

namespace mousdraw
{
public partial class Form1 : Form
{
private bool startdraw = false;//是否开始画图
private Graphics gs;//画版
private Pen pen;//画笔
private Point startpt;//画图起点
public Rectangle taskBarRect;//任务栏位置
public Form1()
{
InitializeComponent();
WindowState = FormWindowState.Maximized;//本窗体最大化
FormBorderStyle = FormBorderStyle.None;//无边框窗体

TransparencyKey = BackColor;//背景透明(鼠标穿透)
DoubleBuffered = true;//双缓存处理

gs = CreateGraphics();//创建窗体画板
pen = new Pen(Color.Black, 3f);//画笔

//taskBarHandle为返回的任务栏的句柄
//Shell_TrayWnd为任务栏的类名
MouseHookProcedure = new HookProc(MouseHookProc); //声明钩子
int taskBarHandle = FindWindow("Shell_TrayWnd", null);
GetWindowRect(taskBarHandle, ref taskBarRect);
newTaskBarRect = new Rectangle(taskBarRect.X, taskBarRect.Y, taskBarRect.Width - taskBarRect.X, taskBarRect.Height - taskBarRect.Y);
StartHook();
}

private int hMouseHook = 0;
private MouseEventArgs mea;//鼠标事件参数
//全局钩子常量
private const int WH_MOUSE_LL = 14;

//声明消息的常量,鼠标按下和释放
private const int WM_LEFT_RBUTTONDOWN = 0x201;//鼠标左键按下事件监听值
private const int WM_LEFT_RBUTTONUP = 0x202;//鼠标左键弹起事件监听值
private const int WM_RIGHT_RBUTTONDOWN = 0x204;//鼠标右键按下事件监听值
private const int WM_RIGHT_RBUTTONUP = 0x205;//鼠标右键按下事件监听值
private const int WM_MOVE = 0x200;//鼠标移动事件监听值

//保存任务栏的矩形区域

public Rectangle newTaskBarRect;

//定义委托
public delegate int HookProc(int nCode, int wParam, IntPtr lParam);
private HookProc MouseHookProcedure;

//寻找符合条件的窗口
[DllImport("user32.dll", EntryPoint = "FindWindow")]
public static extern int FindWindow(
string lpClassName,
string lpWindowName
);

//获取窗口的矩形区域
[DllImport("user32.dll", EntryPoint = "GetWindowRect")]
public static extern int GetWindowRect(
int hwnd,
ref Rectangle lpRect
);

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

//卸载钩子
[DllImport("user32.dll", EntryPoint = "UnhookWindowsHookEx")]
public static extern bool UnhookWindowsHookEx(
int hHook
);

//调用下一个钩子
[DllImport("user32.dll")]
public static extern int CallNextHookEx(
int idHook,
int nCode,
int wParam,
IntPtr lParam
);

//获取当前线程的标识符
[DllImport("kernel32.dll")]
public static extern int GetCurrentThreadId();

//获取一个应用程序或动态链接库的模块句柄
[DllImport("kernel32.dll")]
public static extern IntPtr GetModuleHandle(string name);

//鼠标结构，保存了鼠标的信息
[StructLayout(LayoutKind.Sequential)]
public struct MOUSEHOOKSTRUCT
{
public Point pt;
public int hwnd;
public int wHitTestCode;
public int dwExtraInfo;
}

/// <summary>
/// 安装钩子
/// </summary>
private void StartHook()
{
if (hMouseHook == 0)
{
hMouseHook = SetWindowsHookEx(WH_MOUSE_LL, MouseHookProcedure, GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName), 0);
if (hMouseHook == 0)
{//如果设置钩子失败.
this.StopHook();
MessageBox.Show("Set windows hook failed!");
}
}
}

/// <summary>
/// 卸载钩子
/// </summary>
private void StopHook()
{
bool stop = true;

if (hMouseHook != 0)
{
stop = UnhookWindowsHookEx(hMouseHook);
hMouseHook = 0;

if (!stop)
{//卸载钩子失败
MessageBox.Show("Unhook failed!");
}
}
}

private int MouseHookProc(int nCode, int wParam, IntPtr lParam)
{
if (nCode >= 0)
{
//把参数lParam在内存中指向的数据转换为MOUSEHOOKSTRUCT结构
MOUSEHOOKSTRUCT mouse = (MOUSEHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(MOUSEHOOKSTRUCT));//鼠标
mea = new MouseEventArgs(MouseButtons.Left, 1, mouse.pt.X, mouse.pt.Y, 0);
//这句为了看鼠标的位置
this.Text = "MousePosition:" + mouse.pt.ToString();
mousdraw_MouseMove(mea);

if (wParam == WM_LEFT_RBUTTONDOWN || wParam == WM_LEFT_RBUTTONUP || wParam == WM_RIGHT_RBUTTONDOWN || wParam == WM_RIGHT_RBUTTONUP)
{ //鼠标按下或者释放时候截获

if (newTaskBarRect.Contains(mouse.pt))
{ //当鼠标在任务栏的范围内
//如果返回1，则结束消息，这个消息到此为止，不再传递。
//如果返回0或调用CallNextHookEx函数则消息出了这个钩子继续往下传递，也就是传给消息真正的接受者
return 0;
}
else if (wParam == WM_LEFT_RBUTTONDOWN)
{
return mousdraw_MouseDown(mea);
}
else if (wParam == WM_LEFT_RBUTTONUP)
{
return mousdraw_MouseUp(mea);
}
else
{
return 1;
}
}
}
return CallNextHookEx(hMouseHook, nCode, wParam, lParam);
}

private int mousdraw_MouseDown(MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
startdraw = true;//开始画图
startpt = e.Location;
}
return 1;
}

private int mousdraw_MouseMove(MouseEventArgs e)
{
if (startdraw)
{
gs.DrawLine(pen, startpt, e.Location);
startpt = e.Location;
}
return 0;
}

private int mousdraw_MouseUp(MouseEventArgs e)
{
startdraw = false;//结束画图
return 1;
}

}
}

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