How to remove workspace tab without errors

[Anonymous]

Hi

I want to remove the workspace tab by "RemoveTabFromWorkspace" mehtod, but sometimes it will throw an exception and tell me "Object reference not set to an instance of an object." I don't know the reason. I want to know whether any other ways can also remove the workspace tab.

YU

[Anonymous]

By the way, I want to know why it will throw this exception, I see the workspace really contains the tab which I want to remove.