上个示例是

在原来代码上加入窗体透明，控件不透明代码：

1 using System; 2 using System.Runtime.InteropServices; 3 using System.Windows.Forms; 4  5 namespace HoverTreeWinForm 6 { 7 public partial class FormHewenqi : Form 8 { 9 10 /// 
11 /// 使窗体透明 by 何问起12 /// 
13 protected override CreateParams CreateParams14 {15 get16 {17 18 CreateParams parameter = base.CreateParams;19 parameter.ExStyle |= 0x00080000;20 return parameter;21 22 }23 }24 25 /// 
26 /// http://hovertree.com/h/bjaf/v4y0b2l6.htm27 /// 
28 /// 
     29 [DllImport("User32.dll")]30 public static extern int MessageBox(int h, string m, string c, int type);31 public FormHewenqi()32 {33 InitializeComponent();34 //使控件不透明35 this.TransparencyKey = BackColor;36 }37 38 private void button_hewenqi_Click(object sender, EventArgs e)39 {40 MessageBox(0, "Hello Win32 API HoverTree", "何问起网", 4);41 }42 43 private void linkLabel_help_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)44 {45 System.Diagnostics.Process.Start("http://hovertree.com/h/bjaf/v4y0b2l6.htm");46 }47 48 private void button_hoverc_Click(object sender, EventArgs e)49 {50 //获取主窗体句柄51 IntPtr h_handle = HewenqiUser32.GetCurrentWindowHandle();52 int h_jubing = 0; ;53 if (h_handle != IntPtr.Zero)54 h_jubing = (int)(h_handle);55 MessageBox(h_jubing, "Hello hovertree.com", "欢迎光临何问起", 4);56 }57 }58 }

1、先把窗体的颜色变成一种很不常见的颜色。 

2、把该窗体的TransparecyKey的颜色设置成窗体的颜色。 

3、加入控件，但是控件的颜色不能和窗体颜色一致，否则控件也透明。 

运行程序后，就只能看见标题栏和控件了。

转自：

演示下载： g56m

源码下载：