c sharp WinForm window minimized to system tray

this.SizeChanged += new System.EventHandler(this.Form1_SizeChanged); 
// The top line is the main form InitializeComponent() The reference to be added to the method  
private void Form1_SizeChanged(object sender, EventArgs e) 
{ 
if(this.WindowState == FormWindowState.Minimized) 
{ 
this.Hide(); 
this.notifyIcon1.Visible=true; 
} 
} 

this.notifyIcon1 = new System.Windows.Forms.NotifyIcon(this.components); 
this.NicontextMenu = new System.Windows.Forms.ContextMenu(); 
this.menuItem_Hide = new System.Windows.Forms.MenuItem(); 
this.menuItem_Show = new System.Windows.Forms.MenuItem(); 
this.menuItem_Aubot = new System.Windows.Forms.MenuItem(); 
this.menuItem_Exit = new System.Windows.Forms.MenuItem(); 
this.notifyIcon1.ContextMenu = this.NicontextMenu; 
this.notifyIcon1.Icon = ((System.Drawing.Icon)(resources.GetObject( "NotifyIcon.Icon "))); 
this.notifyIcon1.Text = " "; 
this.notifyIcon1.Visible = true; 
this.notifyIcon1.DoubleClick += new System.EventHandler(this.notifyIcon1_DoubleClick); 
this.notifyIcon1.Click += new System.EventHandler(this.notifyIcon1_Click); 
this.NicontextMenu.MenuItems.AddRange( 
new System.Windows.Forms.MenuItem[] 
{ 
this.menuItem_Hide, 
this.menuItem_Show, 
this.menuItem_Aubot, 
this.menuItem_Exit 
} 
); 
// 
// menuItem_Hide 
// 
this.menuItem_Hide.Index = 0; 
this.menuItem_Hide.Text = " hidden  "; 
this.menuItem_Hide.Click += new System.EventHandler(this.menuItem_Hide_Click); 
// 
// menuItem_Show 
// 
this.menuItem_Show.Index = 1; 
this.menuItem_Show.Text = " According to  "; 
this.menuItem_Show.Click += new System.EventHandler(this.menuItem_Show_Click); 
// 
// menuItem_Aubot 
// 
this.menuItem_Aubot.Index = 2; 
this.menuItem_Aubot.Text = " about  "; 
this.menuItem_Aubot.Click += new System.EventHandler(this.menuItem_Aubot_Click); 
// 
// menuItem_Exit 
// 
this.menuItem_Exit.Index = 3; 
this.menuItem_Exit.Text = " exit  "; 
this.menuItem_Exit.Click += new System.EventHandler(this.menuItem_Exit_Click); 
protected override void OnClosing(CancelEventArgs e) 
{ 
this.ShowInTaskbar = false; 
this.WindowState = FormWindowState.Minimized; 
e.Cancel = true; 
} 
protected override void OnClosing(CancelEventArgs e) 
{ 
//this.ShowInTaskbar = false; 
this.WindowState = FormWindowState.Minimized; 
e.Cancel = true; 
} 
private void CloseCtiServer() 
{ 
timer.Enabled = false; 
DJ160API.DisableCard(); 
this.NotifyIcon.Visible = false; 
this.Close(); 
this.Dispose(); 
Application.Exit(); 
} 
private void HideCtiServer() 
{ 
this.Hide(); 
} 
private void ShowCtiServer() 
{ 
this.Show(); 
this.WindowState = FormWindowState.Normal; 
this.Activate(); 
} 
private void CtiManiForm_Closing(object sender, System.ComponentModel.CancelEventArgs e) 
{ 
this.CloseCtiServer(); 
} 
private void menuItem_Show_Click(object sender, System.EventArgs e) 
{ 
this.ShowCtiServer(); 
} 
private void menuItem_Aubot_Click(object sender, System.EventArgs e) 
{ 
} 
private void menuItem_Exit_Click(object sender, System.EventArgs e) 
{ 
this.CloseCtiServer(); 
} 
private void menuItem_Hide_Click(object sender, System.EventArgs e) 
{ 
this.HideCtiServer(); 
} 
private void CtiManiForm_SizeChanged(object sender, System.EventArgs e) 
{ 
if(this.WindowState == FormWindowState.Minimized) 
{ 
this.HideCtiServer(); 
} 
} 
private void notifyIcon1_DoubleClick(object sender,System.EventArgs e) 
{ 
this.ShowCtiServer(); 
}