void header_Delete(object sender, RoutedEventArgs e)
        {
            //-->删除当前点击的TabItem
            TabItemHeader btn = sender as TabItemHeader;

            if (null == btn || null == btn.Tag)
            {
                return;
            }
            TabItem      ti  = btn.Tag as TabItem;
            PageWorkArea pwa = ti.Content as PageWorkArea;

            pwa.ControlPosition -= pwa_ControlPosition;
            pwa.ContentUpdate   -= pwa_ContentUpdate;
            pwa.Dispose();
            pwa.ParentControl = null;
            pwa = null;
            btn.OnCloseTabItem -= header_Delete;
            tcCollection.Items.Remove(ti);
            ti.Content = null;
            ti         = null;

            var cpwa = CurrentPageWorkArea;

            if (null == cpwa)
            {
                //-->清空属性控件,和文本大刚。
                if (null != OnClear)
                {
                    OnClear(this, null);
                }
                return;
            }
            //-->更新当前的属性控件
            //-->更新文本大刚
            CurrentPageWorkArea.UpdatePropertyGridAndControlTree();
        }