public FormMain() { InitializeComponent(); //显示树窗口 frTree = new FormTreeLeft(); frTree.formParent = this; frTree.Show(dockPanel1); //显示附件窗口 Attachment.ActiveNodeId = "-1"; FormAttachment frmAttchment = new FormAttachment(); Attachment.AttForm = frmAttchment; frmAttchment.Show(dockPanel1); }