C# 桌面上直接绘制

 

1、名字空间 

using System.Runtime.InteropServices;

 

2、API函数申明

[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
public static extern IntPtr GetDesktopWindow();//该函数返回桌面窗口的句柄。
[DllImport("user32.dll", EntryPoint = "GetDCEx", CharSet = CharSet.Auto, ExactSpelling = true)]
private static extern IntPtr GetDCEx(IntPtr hWnd, IntPtr hrgnClip, int flags); //获取显示设备上下文环境的句柄

 

3、绘制代码

        private void button4_Click(object sender, EventArgs e)
        {
            IntPtr desk = GetDesktopWindow();
            IntPtr deskDC = GetDCEx(desk, IntPtr.Zero, 0x403);
            Graphics g = Graphics.FromHdc(deskDC);
            g.DrawString("测试", new Font("宋体", 50, FontStyle.Bold), Brushes.Red, new PointF(100, 100));
        }