集合删除要倒序处理,原因可以参考这个:http://www.foxtable.com/webhelp/topics/0599.htm
For i As Integer = DataTables.Count - 1 To 0 Step - 1
Dim dt As DataTable = DataTables(i)
Select Case dt.Name
Case "导航", "系统_系统设置", "系统_角色"
Case Else
DataTables.Unload(dt.Name)
End Select
Next