void BuildDockingLayout()
{
dockManager.Content = null;
trv = new System.Windows.Controls.TreeView();
TreeViewItem tvitem = GetTreeView("recorded_vid", "Recorded Video", @"C:\Users\UA\Documents\Project\Displayer\P001DS004Tvs2012\Icon\Video Call-50.png");
trv.Items.Add(tvitem);
foreach(var video in dbController.list_video()){
((TreeViewItem)trv.Items[0]).Items.Add(new TreeViewItem() { Header = video });
}
trv.MouseDoubleClick += trv_NodeMouseDoubleClick;
var treeviewContent_right = new DockableContent() { Title = "Video Lists", Content = trv };
treeviewContent_right.Show(dockManager, AnchorStyle.Right);
var treeviewContent_left = new DockableContent() { Title = "Device Lists", Content = new System.Windows.Controls.TextBox() { Text = "Device Lists", IsReadOnly = true } };
treeviewContent_left.Show(dockManager, AnchorStyle.Left);
treeviewContent_left.ToggleAutoHide();
videoPanel.ShowAsDocument(dockManager);
}