/// <summary>
        /// 创建一个新页面
        /// </summary>
        public void CreateNewTab(string url)
        {
            var newTab = new BrowserTabViewModel(url);

            BrowserTabs.Add(newTab);
            SelectedTabIndex = BrowserTabs.IndexOf(newTab);
            OnPropertyChanged("BrowserTabs");
        }
        /// <summary>
        /// 关闭当前页面
        /// </summary>
        private void CloseTab(BrowserTabViewModel closedTab)
        {
            if (BrowserTabs.Count > 0 && BrowserTabs.Contains(closedTab))
            {
                BrowserTabs.Remove(closedTab);
                closedTab.Dispose();
            }

            if (BrowserTabs.Count <= 0)
            {
                OpenNewTab();
            }
        }