给窗体加个圣诞帽——抛砖引玉

 1 using System;
 2  using System.Collections.Generic;
 3  using System.ComponentModel;
 4  using System.Data;
 5 using System.Drawing;
 6 using System.Linq;
 7 using System.Text;
 8 using System.Windows.Forms;
 9 using System.Runtime.InteropServices;
10 
11 namespace Hat
12 {
13     public partial class Form1 : Form
14     {
15         FrmHat hat = new FrmHat();
16 
17         [DllImport("user32.dll", EntryPoint = "GetForegroundWindow")]
18         public static extern IntPtr GetForegroundWindow();      
19 
20         [DllImport("user32.dll")]
21         [return: MarshalAs(UnmanagedType.Bool)]
22         static extern bool GetWindowRect(IntPtr hWnd, ref RECT lpRect);
23          
24         public Form1()
25         {
26             InitializeComponent();           
27             hat.Location = new Point(this.Location.X - 30, this.Location.Y - 10);
28             hat.Show();           
29         }
30 
31 
32         [StructLayout(LayoutKind.Sequential)]
33         public struct RECT
34         {
35             public int Left;                             //最左坐标
36             public int Top;                             //最上坐标
37             public int Right;                           //最右坐标
38             public int Bottom;                        //最下坐标
39         }
40 
41         private void timer1_Tick(object sender, EventArgs e)
42         {            
43             IntPtr ip = GetForegroundWindow();
44             RECT rect = new RECT();
45             GetWindowRect(ip, ref rect);
46 
47             hat.Location = new Point(rect.Left - 30,rect.Top - 10);
48         }
49     }
50 }
51