dotnet/Documentation/compatibility/winforms-accessibility-changes-472.md

Accessibility improvements in Windows Forms controls for .NET 4.7.2

Scope

Major

Version Introduced

4.7.2

Source Analyzer Status

NotPlanned

Change Description

Windows Forms Framework is improving how it works with accessibility technologies to better support Windows Forms customers. These include the following changes:

• Changes to improve display during High Contrast mode.

• Changes to improve the keyboard navigation in the DataGridView and MenuStrip controls.

• Changes to interaction with Narrator.

• Quirked

• Build-time break

Recommended Action

How to opt in or out of these changes

In order for the application to benefit from these changes, it must run on the .NET Framework 4.7.2 or later. The application can benefit from these changes in either of the following ways:

• It is recompiled to target the .NET Framework 4.7.2. These accessibility changes are enabled by default on Windows Forms applications that target the .NET Framework 4.7.2 or later.
• It targets the .NET Framework 4.7.1 or earlier version and opts out of the legacy accessibility behaviors by adding the following AppContext Switch to the <runtime> section of the app config file and setting it to false, as the following example shows.

    <?xml version="1.0" encoding="utf-8"?>
    <configuration>
      <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7"/>
      </startup>
      <runtime>
        <!-- AppContextSwitchOverrides value attribute is in the form of 'key1=true|false;key2=true|false  -->
        <AppContextSwitchOverrides value="Switch.UseLegacyAccessibilityFeatures=false;Switch.UseLegacyAccessibilityFeatures.2=false" />
      </runtime>
    </configuration>

Note that to opt in to the accessibility features added in .NET Framework 4.7.2, you must also opt in to accessibility features of .NET Framework 4.7.1 as well. Applications that target the .NET Framework 4.7.2 or later and want to preserve the legacy accessibility behavior can opt in to the use of legacy accessibility features by explicitly setting this AppContext switch to true.

Use of OS-defined colors in High Contrast themes

• The drop down arrow arrow of the xref:System.Windows.Forms.ToolStripDropDownButton now uses OS-defined colors in High Contrast theme.
• xref:System.Windows.Forms.Button, xref:System.Windows.Forms.RadioButton and xref:System.Windows.Forms.CheckBox controls with xref:System.Windows.Forms.ButtonBase.FlatStyle set to xref:System.Windows.Forms.FlatStyle.Flat?displayProperty=nameWithType or xref:System.Windows.Forms.FlatStyle.Popup?displayProperty=nameWithType now use OS-defined colors in High Contrast theme when selected. Previously, text and background colors were not contrasting and were hard to read.
• Controls contained within a xref:System.Windows.Forms.GroupBox that has its xref:System.Windows.Forms.Control.Enabled property set to false will now use OS-defined colors in High Contrast theme.
• The xref:System.Windows.Forms.ToolStripButton, xref:System.Windows.Forms.ToolStripComboBox, and xref:System.Windows.Forms.ToolStripDropDownButton controls have an increased luminosity contrast ratio in High Contrast Mode.
• xref:System.Windows.Forms.DataGridViewLinkCell will by default use OS-defined colors in High Contrast mode for the xref:System.Windows.Forms.DataGridViewLinkCell.LinkColor?displayProperty=nameWithType property.

NOTE: Windows 10 has changed values for some high contrast system colors. Windows Forms Framework is based on the 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 file in a test application and uncommenting the following code:

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

Improved Narrator support

• Narrator now announces the value of the xref:System.Windows.Forms.ToolStripMenuItem.ShortcutKeys?displayProperty=nameWithType property when announcing the text of a xref:System.Windows.Forms.ToolStripMenuItem.
• Narrator now indicates when a xref:System.Windows.Forms.ToolStripMenuItem has its xref:System.Windows.Forms.Control.Enabled property set to false.
• Narrator now gives feedback on the state of a check box when the xref:System.Windows.Forms.ListView.CheckBoxes?displayProperty=nameWithType property is set to true.
• Narrator Scan Mode focus order is now consistent with the visual order of the controls on the ClickOnce download dialog window.

Improved DataGridView Accessibility support

• Rows in a xref:System.Windows.Forms.DataGridView can now be sorted using the keyboard. Now a user can use the F3 key in order to sort by the current column.
• When the xref:System.Windows.Forms.DataGridView.SelectionMode?displayProperty=nameWithType is set to xref:System.Windows.Forms.DataGridViewSelectionMode.FullRowSelect?displayProperty=nameWithType, the column header will change color to indicate the current column as the user tabs through the cells in the current row.
• The xref:System.Windows.Forms.DataGridViewCell.DataGridViewCellAccessibleObject.Parent?displayProperty=nameWithType property now returns the correct parent control.

Improved Visual cues

• The xref:System.Windows.Forms.RadioButton and xref:System.Windows.Forms.CheckBox controls with an empty xref:System.Windows.Forms.ButtonBase.Text property will now display a focus indicator when they receive focus.

Improved Property Grid Support

• The xref:System.Windows.Forms.PropertyGrid control child elements now return a true for the xref:System.Windows.Automation.ValuePattern.IsReadOnlyProperty property only when a PropertyGrid element is enabled.
• The xref:System.Windows.Forms.PropertyGrid control child elements now return a false for the xref:System.Windows.Automation.AutomationElement.IsEnabledProperty property only when a PropertyGrid element can be changed by the user.

For an overview of UI automation, see the UI Automation Overview.

Improved keyboard navigation

• xref:System.Windows.Forms.ToolStripButton now allows focus when contained within a xref:System.Windows.Forms.ToolStripPanel that has the xref:System.Windows.Forms.ToolStripPanel.TabStop property set to true

Affected APIs

Category

Windows Forms