flex使用module的一个bug

flex中的模块可是漏洞百出，又一bug：

 

TypeError: Error #1034: Type Coercion failed: cannot convert mx.managers::HistoryManagerImpl@2403de71 to mx.managers.IHistoryManager.
at mx.managers::HistoryManager$/get impl()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\managers\HistoryManager.as:96]
at mx.managers::HistoryManager$/unregister()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\managers\HistoryManager.as:144]
at mx.containers::ViewStack/commitProperties()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\containers\ViewStack.as:651]
at mx.containers::TabNavigator/commitProperties()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\containers\TabNavigator.as:504]
at mx.core::UIComponent/validateProperties()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\core\UIComponent.as:5670]
at mx.managers::LayoutManager/validateProperties()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:519]
at mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:639]
at Function/http://adobe.com/AS3/2006/builtin::apply()
at mx.core::UIComponent/callLaterDispatcher2()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\core\UIComponent.as:8460]
at mx.core::UIComponent/callLaterDispatcher()[E:\dev\3.0.x\frameworks\projects\framework\src\mx\core\UIComponent.as:8403]

 

 

解决方案：

主应用模块添加：

import mx.managers.HistoryManager;
private var hist:HistoryManager;