禁用Windows窗体的关闭按钮

1.

protected override void OnFormClosing(FormClosingEventArgs e)
{
    e.Cancel = true;
    base.OnFormClosing(e);
}

2.

private bool isEnableCloseButton = false;
protected override CreateParams CreateParams
{
     get
     {
         if (isEnableCloseButton)
         {
             CreateParams parameters = base.CreateParams;
             return parameters;
         }
         else
         {
             int CS_NOCLOSE = 0x200;
             CreateParams parameters = base.CreateParams;
             parameters.ClassStyle |= CS_NOCLOSE;
             return parameters;
         }
     }
}