Welcome!

Microsoft Cloud Authors: Kevin Benedict, Pat Romanski, Liz McMillan, Lori MacVittie, Elizabeth White

Blog Feed Post

How to: Use the SharePoint 2013 REST API from a Windows Store App (Windows 8 Metro)

I’ve recently taken an interest to building Windows Store Apps (aka Windows 8 Metro).  Not because I think I can get rich in the Windows Store but because I think it provides a unique way to present SharePoint data.  If you’re like me, you probably assumed Windows Store App development was just like .NET Framework 4.5 development.  You would be wrong.  The .NET Framework is provided by a single assembly reference called .NET for Windows Store Apps.  It has many of the familiar classes that you have come to expect.  My initial thinking was that I could use the SharePoint Client Object Model directly from my app.  That thinking was also wrong.  It turns out that the Client Object Model has a dependency on System.Web.Service.dll which does not exist in .NET for Windows Store Apps.  Simply put, Window Store Apps only support WCF references.  This means that the REST API is now our best choice.

When it comes to Windows Store Apps, you have a few choices on which programming language to use.  Modern JavaScript is not my strong point, so I am going to demonstrate using C#.  Before we dig into the C# code though, we’ll take a look at how to construct the REST URL.  This article on MSDN does a great job explaining the details of how the URL is built.  Essentially we start with the URL to our site (i.e.: http://server/site) and append /_api/web/lists to it along with a method to get a particular list by title, getbytitle.  To get the items of the list we append /items to it.   In my case, I want to pull the tasks list of a site so it would look something like this.

http://server/site/_api/web/list/getbytitle(‘tasks’)/items

You can type this right into your browser and see the XML that the REST API returns.  Here’s an example.

RESTAPIListsBrowser

There is a lot of XML to take in there.  We’re particularly interested in the content element contain in each entry element.  This has the data from our list items.  However, we can reduce the amount of XML returned significantly by using the $select parameter on the REST URL.  In my case I am going to select a few common fields such as Title, DueDate, and Status.  Here is what the URL looks like now.

http://server/site/_api/web/list/getbytitle(‘tasks’)/items?$select=Title,DueDate,Status,PercentComplete

RESTAPIListsWithSelectBrowser

You’ll notice that the results are much more manageable now.  We’ll talk about how we can use LINQ to XML here shortly to parse this data into something usable from our Windows Store app. 

Now let’s look at the code that is required to get the data in our app.  Start by creating a new Windows Store App in Visual Studio 2012.  You can do this by choosing your language (C#) and then Windows Store –> Blank App (XAML).

VS12NewWindowsStoreApp

If this is the first Windows Store App you have started in Visual Studio, you will be prompted for your Windows Live credentials.  This allows you to get a certificate so that you can build apps locally.  In our app, we want to bind data, so I am going to create a new Items Page.  This template has many of the components you need to get started quickly with data binding.

VS12NewItemsPage

When adding the page, you will be prompted to add some dependent files.  Click yes and then you should see your design surface.  Now, open the code-behind of your Items page.  In the LoadState method, we will start the process of retrieving our data and binding it.  We rely on some asynchronous calls to get data from REST, so we will need to put this data in another method and use the async keyword.

protected override void LoadState(Object navigationParameter, Dictionary<String, Object> pageState)

{

    // TODO: Assign a bindable collection of items to this.DefaultViewModel["Items"]

    BindData();

}

 

private async void BindData()

{

 

}

Before we start writing the method though, we need to include a few using statements.

using System.Net;

using System.Net.Http;

using System.Xml;

using System.Xml.Linq;

If you have looked at any of the other C# examples for working with the REST API, you will know they are heavily dependent on the HttpWebRequest object.  However, with Windows Store Apps, we have to use HttpClient instead. We’ll start by defining our REST URL from up above.

string restUrl = "http://server/_api/lists/getbytitle('tasks')/items?$select=Title,DueDate,Body,Status,PercentComplete";

To handle authentication we first need to create an HttpClientHandler object.  We want to automatically use the credentials of the currently logged in user so this is required.  To enable this, just set UseDefaultCredentials to true.  There are also other settings required which we’ll talk about below.

HttpClientHandler httpClientHandler = new HttpClientHandler();

httpClientHandler.UseDefaultCredentials = true;

We can now create the HttpClient object by passing the HttpClientHandler to the constructor.

HttpClient client = new HttpClient(httpClientHandler);

We then need to tell the REST API, that we want the result back as ATOM / XML as opposed to JSON.  We do this by setting a few headers.

client.DefaultRequestHeaders.Add("Accept", "application/atom+xml");

client.DefaultRequestHeaders.Add("ContentType", "application/atom+xml;type=entry");

Now, we can send the request to SharePoint and wait for a response.  We use the await keyword on the GetAsync() method which is why we needed the async keyword on the method signature.  The EnsureSuccessStatusCode() method simply throws an exception if a valid 200 HTTP response is not received.

var response = await client.GetAsync(restUrl);

response.EnsureSuccessStatusCode();

At this point our data has been received back at the client from SharePoint.  Now we need to begin the fun process of parsing it and binding it.  We get the raw string XML data with the following method (also asynchronous).  You could run the app at this point (with a few tweaks) if you wanted to see it in the debugger but we haven’t done anything wit the data yet.

string

responseBody = await response.Content.ReadAsStringAsync();

Now we need to read the XML into an XDocument object so that we can use LINQ to XML to parse it.

StringReader reader = new StringReader(responseBody);

XDocument responseXml = XDocument.Load(reader, LoadOptions.None);

Now we have the data into something queryable.  However, what we really need is a custom object that we can bind to.  If you look back at the XML, you might have noticed a few namespaces in use in the XML document.  We need to define those or our queries will never work.

XNamespace atom = "http://www.w3.org/2005/Atom";

XNamespace d = "http://schemas.microsoft.com/ado/2007/08/dataservices";

XNamespace m = "http://schemas.microsoft.com/ado/2007/08/dataservices/metadata";

Now, we can use LINQ to XML to select the data into a new anonymous type.  If you look at the XML again, we want to query entry elements using the Descendants() method and then the actual values we want are inside the nested Content and then Properties elements.  The data is heavily nested so it makes our LINQ to XML a little messy.  It’s not too bad though.  For the non-string values, I parse the data into the type that I want it (i.e.: DateTime).

var items = from item in responseXml.Descendants(atom + "entry")

            select new

            {

                Title = item.Element(atom + "content").Element(m + "properties").Element(d + "Title").Value,

                DueDate = DateTime.Parse(item.Element(atom + "content").Element(m + "properties").Element(d + "DueDate").Value),

                Status = item.Element(atom + "content").Element(m + "properties").Element(d + "Status").Value,

                PercentComplete = decimal.Parse(item.Element(atom + "content").Element(m + "properties").Element(d + "PercentComplete").Value)

            };

Now, we have data that can be bound to the GridView / ListView on the Items Page.  To bind we assign our data source as follows:

this

.DefaultViewModel["Items"] = items;

Just like Windows Phone and SharePoint apps need to declare the capabilities of the application, Windows Store Apps are no different.  To do this, open Package.appmanifest.  In our case, we need to declare that we intend to communicate over the internal network (Private Networks) and that we need Enterprise Authentication.  The latter allows the app to authenticate with the current user’s domain credentials automatically.  If you don’t have this capability set, you are guaranteed a 401 Access Denied or Unable to connect to remote server error.

Windows8ProjectCapabilities

We can now run the app.  However, there is one last thing we need to do.  We need a way to navigate to the TaskItemsPage that we created.  It loads MainPage by default.  Without getting to deep into how Windows Store app navigation works, we’ll just throw a button on the MainPage and then navigate to the TaskItemsPage when clicked.  You can drag and drop a button onto the MainPage using the designer.  Double click on it and it will create the event handling method.  Then we use Frame.Navigate() and pass it the type of page we want to go to, TaskItemsPage.  Here is the code.

private void Button_Click_1(object sender, RoutedEventArgs e)

{

    Frame.Navigate(typeof(TasksItemsPage));

}

Run your app, and click on the button to navigate to your TaskItemsPage.  If all goes well, you won’t receive any errors and you’ll see a page like the screen below.  Note, that your application doesn’t currently have any way to exit.  To get out you either need to Alt+Tab or move your mouse to the Top-Left corner of the screen to switch to the desktop.

Windows8TasksItemsPage

This is great, but we’re not using all of our data yet.  By default, it will bind the Title for us.  However, we want to display some of our additional fields though.  To do this, we can create a DataTemplate.  We need to look into how it works first though.  Locate the GridView in your XAML file.  It should look something like this.

<GridView

    x:Name="itemGridView"

    AutomationProperties.AutomationId="ItemsGridView"

    AutomationProperties.Name="Items"

    TabIndex="1"

    Grid.RowSpan="2"

    Padding="116,136,116,46"

    ItemsSource="{Binding Source={StaticResource itemsViewSource}}"

    ItemTemplate="{StaticResource Standard250x250ItemTemplate}"

    SelectionMode="None"

    IsSwipeEnabled="false"/>

Notice the ItemTemplate and how it is bound to Standard250x250ItemTemplate.  This template can actually be found in StandardStyles.xaml

<DataTemplate x:Key="Standard250x250ItemTemplate">

    <Grid HorizontalAlignment="Left" Width="250" Height="250">

        <Border Background="{StaticResource ListViewItemPlaceholderBackgroundThemeBrush}">

            <Image Source="{Binding Image}" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}"/>

        </Border>

        <StackPanel VerticalAlignment="Bottom" Background="{StaticResource ListViewItemOverlayBackgroundThemeBrush}">

            <TextBlock Text="{Binding Title}" Foreground="{StaticResource ListViewItemOverlayForegroundThemeBrush}" Style="{StaticResource TitleTextStyle}" Height="60" Margin="15,0,15,0"/>

            <TextBlock Text="{Binding Subtitle}" Foreground="{StaticResource ListViewItemOverlaySecondaryForegroundThemeBrush}" Style="{StaticResource CaptionTextStyle}" TextWrapping="NoWrap" Margin="15,0,15,10"/>

        </StackPanel>

    </Grid>

</DataTemplate>

If you look at what it is binding, it’s looking for fields Image, Title, and Subtitle.  We don’t have an image, so we can get rid of that.  In its place, we’ll add the other fields in our dataset.  We don’t want to edit the out-of-the-box template, so we can copy this snippet and add it to the Pages.Resources element in our TaskItemsPage.xaml.  I then changed its name to TaskItemTemplate and added the remaining fields.

<DataTemplate x:Key="TaskItemTemplate">

    <Grid HorizontalAlignment="Left" Width="250" Height="250">

        <StackPanel VerticalAlignment="Top" Background="{StaticResource ListViewItemOverlayBackgroundThemeBrush}">

            <TextBlock Text="{Binding Title}" Foreground="{StaticResource ListViewItemOverlayForegroundThemeBrush}" Style="{StaticResource TitleTextStyle}" Height="60" Margin="15,0,15,0"/>

            <TextBlock Text="{Binding DueDate}" Foreground="{StaticResource ListViewItemOverlaySecondaryForegroundThemeBrush}" Style="{StaticResource CaptionTextStyle}" TextWrapping="NoWrap" Margin="15,0,15,10"/>

            <TextBlock Text="{Binding PercentComplete}" Foreground="{StaticResource ListViewItemOverlaySecondaryForegroundThemeBrush}" Style="{StaticResource CaptionTextStyle}" TextWrapping="NoWrap" Margin="15,0,15,10"/>

            <TextBlock Text="{Binding Status}" Foreground="{StaticResource ListViewItemOverlaySecondaryForegroundThemeBrush}" Style="{StaticResource CaptionTextStyle}" TextWrapping="NoWrap" Margin="15,0,15,10"/>

        </StackPanel>

    </Grid>

</DataTemplate>

Now we just need to change the template name in the GridView to use the TaskItemTemplate.

<GridView

    x:Name="itemGridView"

    AutomationProperties.AutomationId="ItemsGridView"

    AutomationProperties.Name="Items"

    TabIndex="1"

    Grid.RowSpan="2"

    Padding="116,136,116,46"

    ItemsSource="{Binding Source={StaticResource itemsViewSource}}"

    ItemTemplate="{StaticResource TaskItemTemplate}"

    SelectionMode="None"

    IsSwipeEnabled="false"/>

Run the app again and you’ll now have your custom fields bound.  It should look something like this.

Windows8TasksItemsPageCustomTemplate

The DueDate and PercentComplete are not formatted in this case.  I won’t cover that today, but if you look at the Blog Reader example, it explains the techniques you can use to do cool formatting.  The Data Binding article goes into a lot of detail if you want to learn all of the ways you can bind data too.  If you want a good tutorial to start from scratch on a Windows Store App, see the Hello, World example.

This turned out to be quite the long blog post.  I hope you find it useful.  If you find this interesting and you are going to be at SharePoint Conference 2012 in November (SPC12), you should be sure and attend my session Bringing SharePoint to the Desktop: Building Windows Store Apps with SharePoint 2013 (SPC025).

Follow me on twitter @coreyroth.

Read the original blog entry...

More Stories By Corey Roth

Corey Roth, a SharePoint Server MVP, is an independent consultant specializing in Cloud technologies such as Azure and Office 365. He also specializes in mobile development. Corey serves as the product manager for two cloud-first mobile app platforms: BrewZap and HappenZap.

IoT & Smart Cities Stories
When talking IoT we often focus on the devices, the sensors, the hardware itself. The new smart appliances, the new smart or self-driving cars (which are amalgamations of many ‘things'). When we are looking at the world of IoT, we should take a step back, look at the big picture. What value are these devices providing. IoT is not about the devices, its about the data consumed and generated. The devices are tools, mechanisms, conduits. This paper discusses the considerations when dealing with the...
SYS-CON Events announced today that IoT Global Network has been named “Media Sponsor” of SYS-CON's @ThingsExpo, which will take place on June 6–8, 2017, at the Javits Center in New York City, NY. The IoT Global Network is a platform where you can connect with industry experts and network across the IoT community to build the successful IoT business of the future.
IoT is rapidly becoming mainstream as more and more investments are made into the platforms and technology. As this movement continues to expand and gain momentum it creates a massive wall of noise that can be difficult to sift through. Unfortunately, this inevitably makes IoT less approachable for people to get started with and can hamper efforts to integrate this key technology into your own portfolio. There are so many connected products already in place today with many hundreds more on the h...
The best way to leverage your Cloud Expo presence as a sponsor and exhibitor is to plan your news announcements around our events. The press covering Cloud Expo and @ThingsExpo will have access to these releases and will amplify your news announcements. More than two dozen Cloud companies either set deals at our shows or have announced their mergers and acquisitions at Cloud Expo. Product announcements during our show provide your company with the most reach through our targeted audiences.
CloudEXPO New York 2018, colocated with DXWorldEXPO New York 2018 will be held November 11-13, 2018, in New York City and will bring together Cloud Computing, FinTech and Blockchain, Digital Transformation, Big Data, Internet of Things, DevOps, AI, Machine Learning and WebRTC to one location.
Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settlement products to hedge funds and investment banks. After, he co-founded a revenue cycle management company where he learned about Bitcoin and eventually Ethereal. Andrew's role at ConsenSys Enterprise is a mul...
Disruption, Innovation, Artificial Intelligence and Machine Learning, Leadership and Management hear these words all day every day... lofty goals but how do we make it real? Add to that, that simply put, people don't like change. But what if we could implement and utilize these enterprise tools in a fast and "Non-Disruptive" way, enabling us to glean insights about our business, identify and reduce exposure, risk and liability, and secure business continuity?
DXWorldEXPO | CloudEXPO are the world's most influential, independent events where Cloud Computing was coined and where technology buyers and vendors meet to experience and discuss the big picture of Digital Transformation and all of the strategies, tactics, and tools they need to realize their goals. Sponsors of DXWorldEXPO | CloudEXPO benefit from unmatched branding, profile building and lead generation opportunities.
DXWorldEXPO LLC announced today that Telecom Reseller has been named "Media Sponsor" of CloudEXPO | DXWorldEXPO 2018 New York, which will take place on November 11-13, 2018 in New York City, NY. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
Digital Transformation: Preparing Cloud & IoT Security for the Age of Artificial Intelligence. As automation and artificial intelligence (AI) power solution development and delivery, many businesses need to build backend cloud capabilities. Well-poised organizations, marketing smart devices with AI and BlockChain capabilities prepare to refine compliance and regulatory capabilities in 2018. Volumes of health, financial, technical and privacy data, along with tightening compliance requirements by...