（一）C# Windows Mobile 半透明窗体

 1 using System;
 2 
 3 using System.Collections.Generic;
 4 using System.ComponentModel;
 5 using System.Data;
 6 using System.Drawing;
 7 using System.Text;
 8 using System.Windows.Forms;
 9 using System.Runtime.InteropServices;
10 
11 namespace Demo01
12 {
13     public partial class Form1 : Form
14     {
15         public Form1()
16         {
17             InitializeComponent();
18         }
19 
20         [DllImport("coredll.dll")]
21         public extern static IntPtr GetDesktopWindow();
22 
23         [DllImport("coredll.dll")]
24         public extern static bool SetLayeredWindowAttributes(IntPtr hwnd, uint crKey, byte bAlpha, uint dwFlags);
25         public static uint LWA_COLORKEY = 0x00000001;
26         public static uint LWA_ALPHA = 0x00000002;
27 
28         [DllImport("coredll.dll")]
29         public extern static uint SetWindowLong(IntPtr hwnd, int nIndex, uint dwNewLong);
30         [DllImport("coredll.dll")]
31         public extern static uint GetWindowLong(IntPtr hwnd, int nIndex);
32 
33         public enum WindowStyle : int
34         {
35             GWL_EXSTYLE = -20
36         }
37 
38         public enum ExWindowStyle : uint
39         {
40             WS_EX_LAYERED = 0x00080000
41         }
42 
43         private void SetWindowTransparent(byte bAlpha)
44         {
45             try
46             {
47                 SetWindowLong(this.Handle, (int)WindowStyle.GWL_EXSTYLE,
48                     GetWindowLong(this.Handle, (int)WindowStyle.GWL_EXSTYLE) | (uint)ExWindowStyle.WS_EX_LAYERED);
49 
50                 SetLayeredWindowAttributes(this.Handle, 0, bAlpha, LWA_ALPHA);
51 
52             }
53             catch
54             {
55             }
56         }
57 
58         private void button1_Click(object sender, EventArgs e)
59         {
60             this.Close();
61         }
62 
63         private void trackBar1_ValueChanged(object sender, EventArgs e)
64         {
65             label1.Text = "透明度(0~255): " + trackBar1.Value.ToString();
66             SetWindowTransparent(Convert.ToByte(trackBar1.Value));
67         }
68 
69         private void Form1_Load(object sender, EventArgs e)
70         {
71             Rectangle rf = Screen.PrimaryScreen.WorkingArea;
72 
73             this.Location = new Point((rf.Width - this.Width) / 2, (rf.Height - this.Height) / 2);
74 
75             //SetWindowTransparent(136);
76         }
77     }
78 }