dotnet/Documentation/breaking-changes

.NET Framework Breaking Changes

The following documents provide information on .NET Framework breaking changes and changes in behavior, starting with .NET Framework 4.5.

• SoapFormatter cannot deserialize Hashtable and similar ordered collection objects
• XML schema validation is stricter
• WPF DataTemplate elements are now visible to UIA
• WPF TextBox selected text appears a different color when the text box is inactive
• List<T>.ForEach can throw exception when modifying list item
• System.Uri parsing adheres to RFC 3987
• System.Uri escaping now supports RFC 3986 (http://tools.ietf.org/html/rfc3986)
• System.Net.PeerToPeer.Collaboration unavailable on Windows 8
• MEF catalogs implement IEnumerable and therefore can no longer be used to create a serializer
• Missing Target Framework Moniker results in 4.0 behavior
• No longer able to set EnableViewStateMac to false
• BlockingCollection<T>.TryTakeFromAny does not throw anymore
• XmlSchemaException now sets line positions properly
• System.Activities is now APTCA
• WorkFlow 3.0 types are obsolete
• Some WorkFlow drag and drop APIs are obsolete
• New (ambiguous) Dispatcher.Invoke overloads could result in different behavior
• EncoderParameter ctor is obsolete
• EF version must match NetFX version
• Change in behavior for Task.WaitAll methods with time-out arguments
• Change in behavior in Data Definition Language (DDL) APIs
• MachineKey.Encode and MachineKey.Decode methods are now obsolete
• The Replace method in OData URLs is disabled by default
• System.ServiceModel.Web.WebServiceHost object no longer adds a default endpoint
• EventSource.WriteEvent impls must pass WriteEvent the same parameters that it received (plus ID)
• MinFreeMemoryPercentageToActiveService is now respected
• XmlTextReader DTD entity expansion is limited to 10,000,000 characters
• XSLT forward compat now works
• XSLT style sheet exception message changed
• WF serializes Expressions.Literal<T> DateTimes differently now (breaks custom XAML parsers)
• New enum values in WPF's PageRangeSelection
• WPF DispatcherSynchronizationContext.CreateCopy now returns a new copy instead of the current instance
• System.Threading.Tasks.Task no longer throw ObjectDisposedException after object is disposed
• Different exception handling for ObjectContext.CreateDatabase and DbProviderServices.CreateDatabase methods
• ObjectContext.Translate and ObjectContext.ExecuteStoreQuery now support enum type
• Enumerable.Empty<TResult> always returns cached instance
• HttpRequest.ContentEncoding property prohibits UTF7
• HttpUtility.JavaScriptStringEncode escapes ampersand
• Error codes for maxRequestLength or maxReceivedMessageSize are different
• EventListener truncates strings with embedded nulls
• WinRT stream adapters no long call FlushAsync automatically on close
• ObsoleteAttribute exports as both ObsoleteAttribute and DeprecatedAttribute in WinMD scenarios
• ResolveAssemblyReference task now warns on dependencies with the wrong architecture
• Opt-in break to revert from different 4.5 SQL generation to simpler 4.0 SQL generation
• WPF TextBox defaults to undo limit of 100
• WPF TextBox.Text can be out-of-sync with databinding
• WinForm's CheckForOverflowUnderflow property is now true for System.Drawing
• List.Sort algorithm changed
• Exceptions during unobserved processing in System.Threading.Tasks.Task no longer propagate on finalizer thread
• Compiler support for type forwarding when multi-targeting mscorlib
• IAsyncResult.CompletedSynchronously property must be correct for the resulting task to complete
• Log file name created by the ObjectContext.CreateDatabase method has changed to match SQL Server specifications
• Page.LoadComplete event no longer causes System.Web.UI.WebControls.EntityDataSource control to invoke data binding
• WebUtility.HtmlDecode no longer decodes invalid input sequences
• WebUtility.HtmlEncode and WebUtility.HtmlDecode round-trip BMP correctly
• Apps published with ClickOnce that use a SHA-256 code-signing certificate may fail on Windows 2003
• Managed browser hosting controls from the .NET Framework 1.1 and 2.0 are blocked
• Deserialization of objects across appdomains can fail
• DbParameter.Precision and DbParameter.Scale are now public virtual members
• EF no longer throws for QueryViews with specific characteristics
• SqlConnection can no longer connect to SQL Server 1997 or databases using the VIA adapter
• SqlBulkCopy uses destination column encoding for strings
• Sql_variant data uses sql_variant collation rather than database collation
• DataObject.GetData now retrieves data as UTF-8
• Assemblies compiled with Regex.CompileToAssembly breaks between 4.0 and 4.5
• TargetFrameworkName for default app domain no longer defaults to null if not set
• X509Certificate2.ToString(bool) does not throw now when .NET cannot handle the certificate
• Reflection objects can no longer be passed from managed code to out-of-process DCOM clients
• ContentDisposition DateTimes returns slightly different string
• ClickOnce supports SHA-256 on 4.0-targeted apps
• IL ret not allowed in a try region
• XmlWriter throws on invalid surrogate pairs
• WorkflowDesigner.Load doesn't remove symbol property
• SqlConnection.Open fails on Windows 7 with non-IFS Winsock BSP or LSP present
• ICommand.CanExecuteChanged event behaviour changed in .NET 4.5
• Some .NET APIs cause first chance (handled) EntryPointNotFoundExceptions
• Scrolling a WPF TreeView or grouped ListBox in a VirtualizingStackPanel can cause a hang
• WPF spawns a wisptis.exe process which can freeze the mouse
• Unexpected InvalidCastException from InvokeMethod activity in WF4
• Type.IsAssignableFrom returns wrong result for generic variables with constraints
• WPF Aero2 and AeroLite themes toggle button doesn't show any state
• EntityFramework 6.0 loads very slowly in apps launched from Visual Studio
• Multi-line ASP.Net TextBox spacing changed when using AntiXSSEncoder
• Linq to EF Join throws ArgumentOutOfRangeException
• XmlSerializer serializes fields differently in 4.5
• ConcurrentQueue<T>.TryPeek can return an erroneous null via its out parameter
• Profiling ASP.Net MVC4 apps can lead to Fatal Execution Engine Error
• Non-pooled SQL connections will leak memory if not explicitly disposed
• Multiple items in a single TableLayoutPanel cell may be rearranged
• Binding a WPF selector property (such as 'SelectedItem') to a static property does not work
• Foreach iterator variable is now scoped within the iteration, so closure capturing semantics are different (in C#5)
• HtmlTextWriter does not render <br/> element correctly
• ListBoxItem IsSelected binding issue with ObservableCollection<T>.Move
• Right clicking on a WPF DataGrid row header changes the DataGrid selection
• Calling Items.Refresh on a WPF ListBox, ListView, or DataGrid with items selected can cause duplicate items to appear in the element
• ETW EventListeners do not capture events from providers with explicit keywords (like the TPL provider)
• Exception message has changed for failed DataContract serialization in case of an unknown type
• Accessing a WPF DataGrid's selected items from a handler of the DataGrid's UnloadingRow event can cause a NullReferenceException
• Building an Entity Framework edmx with Visual Studio 2013 can fail with error MSB4062 if using the EntityDeploySplit or EntityClean tasks
• NetDataContractSerializer fails to deserialize a ConcurrentDictionary serialized with a different .NET version
• XSD Schema validation now correctly detects violations of unique constraints if compound keys are used and one key is empty
• Calling Attribute.GetCustomAttributes on an indexer property no longer throws AmbiguousMatchException if the ambiguity can be resolved by index's type
• Intermittently unable to scroll to bottom item in ItemsControls (like ListBox and DataGrid) when using custom DataTemplates
• GlyphRun.ComputeInkBoundingBox() and FormattedText.Extent return different values beginning in .NET 4.5
• AppDomainSetup.DynamicBase is no longer randomized by UseRandomizedStringHashAlgorithm
• GridViews with AllowCustomPaging set to true may fire the PageIndexChanging event when leaving the final page of the view
• COR_PRF_GC_ROOT_HANDLEs are not being enumerated by profilers
• IPad should not be used in custom capabilities file because it is now a browser capability
• ADO.NET now attempts to automatically reconnect broken SQL connections
• FlowDocument may show an extra line of text
• System.Uri.IsWellFormedUriString method returns false for relative URIs with a colon char in first segment
• The .NET Framework 4.6 does not use a 4.5.x.x version when registering itself in the registry
• Null coalescer values are not visible in debugger until one step later
• Calling DataGrid.CommitEdit from a CellEditEnding handler drops focus
• ASP.NET MVC now escapes spaces in strings passed in via route parameters
• VB.NET no longer supports partial namespace qualification for System.Windows APIs
• Sharing session state with Asp.Net StateServer requires all servers in the web farm to use the same .NET Framework version
• Two-way data-binding to a property with a non-public setter is not supported
• Marshal.SizeOf and Marshal.PtrToStructure overloads break dynamic code
• PreviewLostKeyboardFocus is called repeatedly if its handler shows a Windows Forms message box
• A ConcurrentDictionary serialized in .NET 4.5 with NetDataContractSerializer cannot be deserialized by .NET 4.5.1 or 4.5.2
• Persian calendar now uses the Hijri solar algorithm
• WPF windows are rendered without clipping when extending outside a single monitor
• WPF spell checking in text-enabled controls will not work in Windows 10 for languages not in the OS's input language list
• Only Tls 1.0, 1.1 and 1.2 protocols supported in System.Net.ServicePointManager and System.Net.Security.SslStream
• Calling CreateDefaultAuthorizationContext with a null argument has changed
• WPF layout rounding of margins has changed
• XmlSerializer fails while serializing a type that hides an accessible member with an inaccessible one
• WPF TreeViewItem must be used within a TreeView
• WCF binding with the TransportWithMessageCredential security mode
• X509CertificateClaimSet.FindClaims Considers All claimTypes
• Application.FilterMessage no longer throws for re-entrant implementations of IMessageFilter.PreFilterMessage
• CurrentCulture is not preserved across WPF Dispatcher operations
• CurrentCulture and CurrentUICulture flow across tasks
• BinaryFormatter can fail to find type from LoadFrom context
• RSACng now correctly loads RSA keys of non-standard key size
• Remove Ssl3 from the WCF TransportDefaults
• Incorrect implementation of MemberDescriptor.Equals
• DataGridCellsPanel.BringIndexIntoView throws ArgumentOutOfRangeException
• Item-scrolling a flat list with items of different pixel-height
• Horizontal scrolling and virtualization
• Items.Clear does not remove duplicates from SelectedItems
• WPF Spell Checking fails in unexpected ways
• SignedXml and EncryptedXml Breaking Changes
• .Net Framework now supports Unicode standard version 8.0 categories
• Path colon checks are stricter
• RSACng.VerifyHash now returns False for any verification failure
• Connection pool blocking period for Azure SQL databases is removed
• Changing the IsEnabled property of the parent of a TextBlock control affects any child controls
• Long path support
• Changes in path normalization
• Calls to ClaimsIdentity constructors
• AesCrytpServiceProvider decryptor provides a reusable transform
• WCF transport security supports certificates stored using CNG
• WCF message security now is able to use TLS1.1 and TLS1.2
• Serialization of control characters with DataContractJsonSerializer is now compatible with ECMAScript V6 and V8
• Throttle concurrent requests per session
• Workflow now throws original exception instead of NullReferenceException in some cases
• WPF Grid allocation of space to star-columns
• WPF Pointer-Based Touch Stack
• WPF Printing Stack Update
• ObjectDisposedException thrown by WPF spellchecker
• RibbonGroup background is set to transparent in localized builds
• Workflow checksums changed from MD5 to SHA1
• NullReferenceException in exception handling code from ImageSourceConverter.ConvertFrom
• CspParameters.ParentWindowHandle now expects HWND value
• CoerceIsSelectionBoxHighlighted
• Workflow SQL persistence adds primary key clusters and disallows null values in some columns
• SslStream supports TLS Alerts