主题：当前窗口改变事件

改成

Dim MainTab As C1Command.C1DockingTab = BaseMainform.Controls("MainPages")
For Each p As object In  MainTab.TabPages
    Dim FormTab As C1Command.C1DockingTab = p.controls(0)
    AddHandler Formtab.SelectedIndexChanging, AddressOf C1DockingTab2_SelectedIndexChanging
Next