var peer = FrameworkElementAutomationPeer.FromElement(myTextBlock);

peer.RaiseAutomationEvent(AutomationEvents.LiveRegionChanged);

High contrast

Starting with the .NET Framework 4.7.1, improvements in high contrast have been made to various WPF controls. They are now visible when the HighContrast theme is set. These include:

• Expander control

  The focus visual for the Expander control is now visible. The keyboard visuals for ComboBox,ListBox, and RadioButton controls are visible as well. For example:

  Before:

  After:

• CheckBox and RadioButton controls

  The text in the CheckBox and RadioButton controls is now easier to see when selected in high contrast themes. For example:

  Before:

  After:

• ComboBox control

  Starting with the .NET Framework 4.7.1, the border of a disabled ComboBox control is the same color as disabled text. For example:

  Before:

  After:

  In addition, disabled and focused buttons use the correct theme color.

  Before:

  After:

  Finally, in the .NET Framework 4.7 and earlier versions, setting a ComboBox control’s style to Toolbar.ComboBoxStyleKey caused the drop-down arrow to be invisible. This issue is fixed starting with the .NET Framework 4.7.1. For example:

  Before:

  After:

• DataGrid control

  Starting with the .NET Framework 4.7.1, the sort indicator arrow in DataGrid controls now uses correct theme colors. For example:

  Before:

  After:

  In addition, in the .NET Framework 4.7 and earlier versions, the default link style changed to an incorrect color on mouse over in high contrast modes. This is resolved starting with the .NET Framework 4.7.1. Similarly, DataGrid checkbox columns uses the expected colors for keyboard focus feedback starting with the .NET Framework 4.7.1.

  Before:

  After:

For more information on WPF accessibility improvements in the .NET Framework 4.7.1, see Accessibility improvements in WPF.

Windows Forms accessibility improvements

In the .NET Framework 4.7.1, Windows Forms (WinForms) includes accessibility changes in the following areas.

Improved display in High Contrast mode

Starting with the .NET Framework 4.7.1, various WinForms controls offer improved rendering in the HighContrast modes available in the operating system. Windows 10 has changed the values for some high contrast system colors, and Windows Forms is based on the Windows 10 Win32 framework. For the best experience, run on the latest version of Windows and opt in to the latest OS changes by adding an app.manifest(vt. 证明，表明；显示) file in a test application and un-comment the Windows 10 supported OS line so that it looks the following:

<!-- Windows 10 -->
<supportedOS Id=”{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}” />

Some examples of high contrast changes include:

• Checkmarks in MenuStrip items are easier to view.

• When selected, disabled MenuStrip items are easier to view.

• Text in a selected Button control contrasts with the selection color.

• Disabled text is easier to read. For example:

  Before:

  After:

• High contrast improvements in the Thread Exception Dialog.

Improved Narrator support

Windows Forms in the .NET Framework 4.7.1 includes the following accessibility improvements for the Narrator:

• The MonthCalendar control can be accessed by the Narrator, as well as by other UI automation tools.

• The CheckedListBox control notifies Narrator when an item's check state has changed so the user is notified that they’ve changed the value of a list item.

• The DataGridViewCell control reports the correct read-only status to Narrator.

• Narrator can now read disabled ToolStripMenuItem text, whereas(conj. 然而；鉴于；反之) previously it would skip over disabled menu items.

Enhanced support for UIAutomation accessibility patterns

Starting with the .NET Framework 4.7.1, developers of accessibility technology tools can leverage common API accessibility patterns and properties for several WinForms controls. These accessibility improvements include:

• The ComboBox and ToolStripSplitButton now support the expand/collapse pattern.

• The DataGridViewCheckBoxCell now supports the toggle pattern.

• The ToolStripItem control supports the Name property and the expand/collapse pattern.

• The NumericUpDown and DomainUpDown controls support the Name property.

Improved property browser experience

Starting with the .NET Framework 4.7.1, Windows Forms includes:

• Better keyboard navigation through the various drop-down selection windows.
• A reduction of unnecessary tab stops.
• Better reporting of control types.
• Improved narrator behavior.

ASP.NET web controls

Starting with the .NET Framework 4.7.1 and Visual Studio 2017 15.3, ASP.NET improves how ASP.NET web controls work with accessibility technology in Visual Studio. Changes include the following:

• Changes to implement missing UI accessibility patterns in controls, like the Add Field dialog in the Details View wizard, or the Configure ListView dialog of the ListView wizard.

• Changes to improve the display in High Contrast mode, like the Data Pager Fields Editor.

• Changes to improve the keyboard navigation experiences for controls, like the Fields dialog in the Edit Pager Fields wizard of the DataPager control, the Configure ObjectContext dialog, or the Configure Data Selection dialog of the Configure Data Source wizard.

.NET SDK Tools

The Configuration Editor Tool (SvcConfigEditor.exe) and Service Trace Viewer Tool (SvcTraceViewer.exe) have been improved by fixing varied accessibility issues. Most of these were small issues, like a name not being defined or certain UI automation patterns not being implemented correctly. While many users won’t be aware of these incorrect values, customers who use assistive technologies like screen readers will find these SDK tools more accessible.

These enhancements change some previous behaviors, such as keyboard focus order.

Windows Workflow Foundation (WF) Workflow Designer

Accessibility changes in the Workflow Designer include the following:

• The tab order changes to left to right and top to bottom in some controls:

  • The initialize correlation window for setting correlation data for the InitializeCorrelationactivity.

  • The content definition window for the Receive, Send, SendReply, and ReceiveReply activities.

• More functions are available via the keyboard:

  • When editing the properties of an activity, property groups can be collapsed by keyboard the first time they are focused.

  • Warning icons are accessible by keyboard.

  • The More Properties button in the Properties window is accessible by keyboard.

  • Keyboard users can access the header items in the Arguments and Variables panes(n. 窗格；边；面；窗格玻璃；嵌板) of the Workflow Designer.

• Improved visibility of items with focus, such as when:

• Adding rows to data grids used by the Workflow Designer and activity designers.

• Tabbing through fields in the ReceiveReply and SendReply activities.

• Setting default values for variables or arguments

• Screen readers can now correctly recognize:

  • Breakpoints set in the workflow designer.

  • The FlowSwitch<T>, FlowDecision, and CorrelationScope activities.

  • The contents of the Receive activity.

  • The Target Type for the InvokeMethod activity.

  • The Exception combo box and the Finally section in the TryCatch activity.

  • The Message Type combo box, the splitter in the Add Correlation Initializers window, the Content Definition window, and the CorrelatesOn Definition window in the messaging activities (Receive, Send, SendReply, and ReceiveReply).

  • State machine transitions(n. 过渡，转变) and transitions destinations(n. 目的地，终点；).
  • Annotations(释文;注释) and connectors on FlowDecision activities.
  • The context (right-click) menus for activities.
  • The property value editors, the Clear Search button, the By Category and Alphabetical(adj. 字母的；[计] 依字母顺序的) sort buttons, and the Expression Editor dialog in the properties grid.
  • The zoom percentage in the Workflow Designer.
  • The separator in Parallel and Pick activities.
  • The InvokeDelegate(vt. 委派…为代表;n. 代表) activity.
  • The Select Types window for dictionary activities (Microsoft.Activities.AddToDictionary<TKey,TValue>, Microsoft.Activities.RemoveFromDictionary<TKey,TValue>, etc.).
  • The Browse and Select .NET Type window.
  • Breadcrumbs(n. 面包碎屑;vt. 在…上覆以面包屑) in the Workflow Designer.