How to make ObservableCollection thread-safe?

Question

System.InvalidOperationException: Collection was modified; enumeration operation may not execute.

I am adding/removing from an ObservableCollection which is not on a UI thread.

I have a method names EnqueueReport to add to the colleciton and a DequeueReport to remove from the colleciton.

The flow of steps is as below :-

1. 1.call EnqueueReport whenever a new report is requested
2. call a method every few seconds to check if the report is generated (this has a foreach loop that checks the generated status of all reports in ObservableCollection)
3. call DequeueReport if the report is generated

I am not much in C# libraries. Can someone please guide me on this?

Answer 1

As of .net framwork 4.5 you can use native collection synchronization.

BindingOperations.EnableCollectionSynchronization(YourCollection, YourLockObject);

YourLockObject is instance of any object e.g. new Object();. Use one per collection.

This eliminates the need of some special class or anything. Just enable and enjoy ;)

[edit] As stated in the comments by Mark and Ed (thanks for clarifying!), this does not relieve you from locking the collection on updates as it just synchonizes the collection-view-binding and does not magically make the collection thread-safe itself. [/edit]

PS: BindingOperations resides in Namespace System.Windows.Data.