Revit API错误提示：Starting a new transaction is not permitted.

Autodesk.Revit.Exceptions.InvalidOperationException:

Starting a new transaction is not permitted.

It could be because another transaction already started and has not been completed yet,

or the document is in a state in which it cannot start a new transaction

(e.g. during failure handling or a read-only mode,which could be either permanent or temporary).

这个错误提示是：

一个事务还没有结束，不可以启动另外一个新事务。

解决的方法是：

用子事务SubTransaction。

即你打算在事务内部重新启动一个事务，就要用SubTransaction

SubTransaction ts = new SubTransaction(uiDoc.Document);

from:http://revit.5d6d.com/thread-1226-1-1.html