>From the docs: "An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying or deleting elements, the enumerator is irrecoverably invalidated and the next call to MoveNext or Reset throws an InvalidOperationException. If the collection is modified between MoveNext and Current, Current will return the element that it is set to, even if the enumerator is already invalidated.
The enumerator does not have exclusive access to the collection; therefore, enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads could still modify the collection, which causes the enumerator to throw an exception. To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads." <Ms-help://MS.VSCC/MS.MSDNVS/cpref/html/frlrfsystemcollectionsienumerato rclasstopic.htm> -----Original Message----- From: dotnet discussion [mailto:[EMAIL PROTECTED]] On Behalf Of Tracy Martin Sent: Monday, April 15, 2002 11:33 AM To: [EMAIL PROTECTED] Subject: [DOTNET] Threading and Enumeration Greetings, Does anyone have any information about how enumerators handle changes in the object during enumeration? Or, more specifically, I have a scenario where I have a collection of objects that potentially being added to by separate threads while being enumerated on another thread. Only one thread would be adding objects at a time (and adding would be synchronized to ensure that only one add operation is happening at a time), but my question revolved around - would the enumerating thread find the newly added objects, or would it be necessary to account for this (by resetting the enumeration after an add, or some other method of notifying the enumerating thread that the underlying collection has changed)? Tracy You can read messages from the DOTNET archive, unsubscribe from DOTNET, or subscribe to other DevelopMentor lists at http://discuss.develop.com. You can read messages from the DOTNET archive, unsubscribe from DOTNET, or subscribe to other DevelopMentor lists at http://discuss.develop.com.
