1.5 KiB
WPF DispatcherSynchronizationContext.CreateCopy now returns a new copy instead of the current instance
Scope
Minor
Version Introduced
4.5
Source Analyzer Status
Available
Change Description
In the .NET Framework 4, DispatcherSynchronizationContext.CreateCopy() returned a reference to the current instance, primarily as a performance optimization. In the .NET Framework 4.5, it returns a new instance which makes it possible for the first time to conclude that equal references indicate the executing thread is in the correct synchronization context. It is unlikely that code that checks the identity of these references will be affected, but because of the change, code that calls DispatcherSynchronizationContext.CreateCopy should be tested as part of migration to the .NET Framework 4.5 or newer.
- Quirked
- Build-time break
Recommended Action
Be aware that DispatcherSynchronizationContext.CreateCopy() will now return a new SynchronizationContext object. Previously, code that used equivalence of references generated this way was not actually checking whether it was in the proper context, but does when built against .NET 4.5 or newer. While unlikely to cause issues, exercising the affected code paths should be enough to determine if this poses any problem.
Affected APIs
M:System.Windows.Threading.DispatcherSynchronizationContext.CreateCopy
Category
Windows Presentation Foundation (WPF)