Home > Articles > Operating Systems, Server > Microsoft Windows Desktop

This chapter is from the book

Creating Your First Windows Store App

Let’s be fearless. In this section, I guide you through building your first Windows Store app. Doing a Hello World app would be predictable and boring. Therefore, I suggest that we do something a little more advanced.

I’ll show you how you can create an app which enables you to take pictures. When you click the Take Picture command in the app bar, you can take a picture, and then the picture is displayed in the app (see Figure 1.6, which shows a picture of my dog Rover).


FIGURE 1.6 Your first Windows Store app

Creating the Visual Studio Project

The first step is to create a Microsoft Visual Studio Project. I used Visual Studio 2013 to create almost all of the code samples for this book. In most cases, I used the free version of Visual Studio—Visual Studio Express 2013 for Windows—which you can download from Microsoft.com.

Go ahead and launch Visual Studio. Next, select the menu option File, New Project. On the left-side of the New Project dialog, select JavaScript and select the Blank App project template. Enter the name App1 for your project and click the OK button (see Figure 1.7).


FIGURE 1.7 Using the Visual Studio New Project dialog

After you create your project, you can see all of the files for your project in the Solution Explorer window (Figure 1.8). When you create a new Windows Store app, you get a default.html file (in the root of your project), a default.js file (in the js folder), and a default.css file (in the css folder). These three files are the starting point for your app.


FIGURE 1.8 Windows Store app default files

Declaring App Capabilities

Before we can jump into writing code, there is one other thing that we must do first. We are building an app that takes pictures. That is scary. Potentially, an app could take pictures of you without your knowledge and send the pictures back to an evil hacker lurking on the Internet (or the CEO of Microsoft).

When your app does something scary, you must declare that your app will do this scary thing up front so the user can consent. You declare the capabilities of your app in your application manifest file. You can open the editor for your application manifest by double-clicking the package.appxmanifest file in the Solution Explorer window.

Click the Capabilities tab to view all of the declared capabilities of your application. For example, if you want your app to be able to record from the computer microphone then you need to select the Microphone capability, or if you want your app to be able to save new photos in the user’s Pictures library then you need to select the Pictures Library capability. For our app, we need to enable the Webcam capability so we can take pictures (see Figure 1.9).


FIGURE 1.9 Enabling the capability to take pictures

When a user first runs our app, the user will need to consent to allowing the app to access the webcam (see Figure 1.10). The user only needs to consent once.


FIGURE 1.10 Asking for consent to access your webcam

Creating the HTML Page

When you create a Windows Store app, you get a default.html file in the root of your application. This is the first page that is opened when you run your app. Let’s go ahead and customize this page for our picture app (see Listing 1.1).

LISTING 1.1 Modified default.html Page

<!DOCTYPE html>
    <meta charset="utf-8" />

    <!-- WinJS references -->
    <link href="//Microsoft.WinJS.2.0/css/ui-dark.css" rel="stylesheet" />
    <script src="//Microsoft.WinJS.2.0/js/base.js"></script>
    <script src="//Microsoft.WinJS.2.0/js/ui.js"></script>

    <!-- App1 references -->
    <link href="/css/default.css" rel="stylesheet" />
    <script src="/js/default.js"></script>

    <img id="imgPhoto" src="/images/placeholder.png" />

    <!-- AppBar Control -->
    <div id="appBar1"
        <button data-win-control="WinJS.UI.AppBarCommand"
                label:'Take Picture',
                tooltip:'Take Picture'

The HTML page in Listing 1.1 has been modified so it contains new content in the body of the page. First, notice that the page contains an IMG tag with the ID imgPhoto. We’ll display the photo which we take from the camera here.

Notice, furthermore, that the page contains a DIV tag with a data-win-control=“WinJS.UI.AppBar” attribute. This is an example of a WinJS control. This control renders an app bar that contains a command for taking a picture (see Figure 1.11).


FIGURE 1.11 The Take Picture command in the app bar

Creating the Style Sheet

When you create a new Windows Store app, you also get a default style sheet named default.css which is located in the css folder. You can modify this file to control the appearance of your app.

For our app, I’ve modified the default.css to format the appearance of the photo. It appears in the IMG tag like this:

#imgPhoto {
    margin: 15px auto;
    border: 10px solid white;
    max-width: 90%;
    max-height: 90%;

Creating the JavaScript File

The third file that we need to modify is the JavaScript file named default.js which is located in the js folder. This file contains all of the code associated with the default.html page.

We are going to delete all of the default content of this file and start over. The complete contents of the modified version of default.js are contained in Listing 1.2.

LISTING 1.2 The default.js JavaScript file

(function () {
    "use strict";

    // Aliases
    var capture = Windows.Media.Capture;

    // Executed immediately after page content is loaded
    function init() {
        // Process all of the controls
        WinJS.UI.processAll().done(function () {
            // References to DOM elements
            var cmdTakePicture = document.getElementById("cmdTakePicture");
            var imgPhoto = document.getElementById("imgPhoto");

            // Handle Take Picture command click
            cmdTakePicture.addEventListener("click", function () {
                var captureUI = new capture.CameraCaptureUI();
                captureUI.photoSettings.format = capture.CameraCaptureUIPhotoFormat.png;
                captureUI.captureFileAsync(capture.CameraCaptureUIMode.photo).done(function (photo) {
                    if (photo) {
                        // Use HTML5 File API to create object URL to refer to the photo file
                        var photoUrl = URL.createObjectURL(photo);

                        // Show photo in IMG element
                        imgPhoto.src = photoUrl;

    document.addEventListener("DOMContentLoaded", init);

There is a lot of interesting stuff happening in the JavaScript code in Listing 1.2. Let’s walk through the code.

First, I’ve created an init() function that is executed when the DOMContentLoaded event is raised. The DOMContentLoaded event is a standard DOM event that is raised when a browser finishes parsing an HTML document.

I put all of my code into the init() function so the code won’t be executed until the DOM is ready. Otherwise, if I attempted to access any of the HTML elements in the page then I would get an exception because the elements would not yet exist.

The first thing that I do within the init() method is call the WinJS.UI.processAll() method. This method processes all of the controls in a page. In particular, it converts the DIV tag with the data-win-control="WinJS.UI.AppBar" attribute into an actual app bar.

Next, I setup an event handler for the Take Picture command. When you click the Take Picture command in the app bar, an instance of the Windows.Media.Capture.CameraCaptureUI class is created. The CameraCaptureUI class is an example of a Windows Runtime class.

The CameraCaptureUI.captureFileAsync() method displays the screen for taking a picture (see Figure 1.12). When you click the OK button, the done() method is called and the picture is displayed in the page.


FIGURE 1.12 The camera capture UI screen

An object URL is created for the photo blob (the actual image data) returned by the captureFileAsync() method by calling the URL.createObjectURL() method. This createObjectURL() method is part of the HTML5 File API.

The photo is displayed in the HTML page with the following line of code:

// Show photo in IMG element
imgPhoto.src = photoUrl;

And that is all there is to it! We built an app that enables us to take pictures from our computer and display the pictures in an HTML page.

Notice that our JavaScript file contains a combination of standard JavaScript methods, HTML5 methods, Windows Library for JavaScript methods, and Windows Runtime methods. This is normal for all of the JavaScript files that you create when creating a Windows Store app.

Running the App

After you create the app, you can run it by pressing the green Run button in the Visual Studio toolbar (see Figure 1.13) or just press the F5 key.


FIGURE 1.13 Running a Windows Store app

Assuming that your laptop or tablet has a camera, you can start taking pictures.

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