Home > Articles > Programming > C#

  • Print
  • + Share This
This chapter is from the book

Making the App Accessible

XAML apps have a number of accessibility features built in, designed to help users with disabilities. You can test this support by enabling various features in the Ease of Access section in the PC Settings app. You can configure Narrator, a screen reader, and witness it convey information about your app with varying degrees of success. (You can quickly toggle Narrator on and off by pressing Windows+Enter.) You can choose a high contrast theme and watch controls used by your app automatically change to match the theme. You can turn off standard animations. And so on.

To make your app usable to the broadest set of customers, including people with disabilities, you should take steps to ensure it works even better with these assistive technologies. In this section, we look at improving the screen reading experience for our HelloRealWorld app, and accounting for high contrast themes.

Improving Screen Reading

If you turn on Narrator and launch the HelloRealWorld app (with English as the Windows default language), you hear the following:

  • “HelloRealWorld window”
  • “Editing”

The first utterance is triggered by the app’s window getting focus, and the second utterance is triggered by the TextBox getting focus (which happens automatically).

This experience isn’t good enough, because Narrator doesn’t report the purpose of the TextBox. To fix this, we need to leverage the UI Automation framework, which is as simple as setting the following automation property on the TextBox:

<TextBox AutomationProperties.Name="Please enter your name"
         Name="nameBox" Margin="12"/>

If you add this property then rerun HelloRealWorld with Narrator on, you will hear the following:

  • “HelloRealWorld window”
  • “Please enter your name”
  • “Editing”

Note that when you give the Go Button focus, such as by pressing Tab, Narrator says:

  • “Go button”

This works automatically, thanks to built-in Button behavior that reports its content to the UI Automation framework.

When you click the Button, however, Narrator gives no indication that text has been added to the screen. If a message is worth showing, then it’s worth hearing as well. To fix this problem, we can add the following automation property to the result TextBlock that identifies it as a live region:

<TextBlock AutomationProperties.LiveSetting="Polite"
           Name="result" FontSize="28" Margin="12"/>

A live region is an area whose content changes. This AutomationProperties.LiveSetting property can be set to one of the following values:

  • Off—This is the default value.
  • Polite—Changes should be communicated, but they should not interrupt the screen reader.
  • Assertive—Changes should be communicated immediately, even if the screen reader is in the midst of speaking.

Live region changes are not detected automatically, however. You must trigger them in C#. In our example, we just need to add an extra line of code to the existing Button_Click event handler:

void Button_Click(object sender, RoutedEventArgs e)
  this.result.Text = this.nameBox.Text;
  // Notify a screen reader to report this text



TextBlock, as with other controls, has a peer class in the Windows.UI.Xaml.Automation.Peers namespace. These classes are named with the pattern ElementNameAutomationPeer, and have several members that are designed for accessibility as well as automated testing.

Handling High Contrast Themes

The built-in controls automatically adjust their appearance when the user enables a high contrast theme. They adjust their colors to match the theme’s eight user-customizable colors, and in some cases they change their rendering in other ways. Because of this, your app can automatically look correct under a high contrast theme without you doing extra work. However, when you use images or hardcoded colors, which are quite common, problems arise. Images can be a problem when they convey information but do not use enough contrast. Hardcoded colors are a problem for the same reason, but also because they can make things completely unreadable when intermixed with colors that drastically change under a high contrast theme. In general, mixing hardcoded colors with dynamic colors can be a recipe for disaster.

HelloRealWorld doesn’t use any images, but Chapter 13 explains how you can provide separate versions of your images that can be used for high contrast themes only.

For HelloRealWorld, the hardcoded blue (or red or green) background color could be problematic as the colors of the other elements change. (Although none of the high contrast themes use blue, red, or green as a text color by default, the user could always choose it for the color of text.) We can fix this in code-behind by checking whether the app is running under high contrast and simply removing the StackPanel’s Background in that case:

public sealed partial class MainPage : Page
  Brush defaultBackground;

  public MainPage()

    // Save the default background for later
    this.defaultBackground = this.stackPanel.Background;

    AccessibilitySettings settings = new AccessibilitySettings();

    // Update the background whenever the theme changes
    settings.HighContrastChanged += OnHighContrastChanged;

    // Set the background appropriately on initialization
    OnHighContrastChanged(settings, null);

  void OnHighContrastChanged(AccessibilitySettings sender, object args)
    this.stackPanel.Background = 
      sender.HighContrast ? null : this.defaultBackground;


Because the user could change the theme while our app is running, we need to handle the HighContrastChanged event to adjust accordingly. The rest of the app’s elements already adjust automatically. Figure 1.14 shows the result of adding this code then running the app under two different high contrast themes. Chapter 18 explains how you can define theme-specific colors without needing to write C# code such as this.


FIGURE 1.14 Removing the explicit StackPanel background makes the app look appropriate under any high contrast theme.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020