if(this.WindowState==FormWindowState.Normal&&this.Visible==true)

{

  this.notifyIcon1.Visible=true;//在通知区显示Form的Icon

  this.WindowState=FormWindowState.Minimized;

  this.Visible=false;

  this.ShowInTaskbar=false;//使Form不在任务栏上显示

}

 private void Form1_FormClosing(object sender, FormClosingEventArgs e)      
  {           
     if (e.CloseReason == CloseReason.UserClosing)//当用户点击窗体右上角X按钮或(Alt + F4)时 发生           
     {                
         e.Cancel = true;                
         this.ShowInTaskbar = false;               
         this.myIcon.Icon = this.Icon;                
         this.Hide();           
     }        
  }               
  
  private void myIcon_MouseClick(object sender, MouseEventArgs e)        
  {           
   if (e.Button == MouseButtons.Right)            
   {                
       myMenu.Show();            
   }            
   
   if (e.Button == MouseButtons.Left)           
    {                
    this.Visible = true;                
    this.WindowState = FormWindowState.Normal;                            
    }        
 }                 
 
 private void toolMenuCancel_Click(object sender, EventArgs e)         
 {             
    Application.Exit();         
 }