Welcome!

Microservices Expo Authors: Elizabeth White, Liz McMillan, Carmen Gonzalez, Pat Romanski, Yeshim Deniz

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 a consultant at Hitachi Consulting specializing in SharePoint and Office 365 for clients in the energy sector. He has more than ten years of experience delivering solutions in the energy, travel, advertising and consumer electronics verticals.

Corey specializes in delivering ECM and search solutions to clients using SharePoint. Corey has always focused on rapid adoption of new Microsoft technologies including Visual Studio 2013, Office 365, and SharePoint.

He is a member of the .NET Mafia (www.dotnetmafia.com) where he blogs about the latest technology and SharePoint. He is dedicated to the community and speaks regularly at user groups and SharePoint Saturdays.

@MicroservicesExpo Stories
More and more companies are looking to microservices as an architectural pattern for breaking apart applications into more manageable pieces so that agile teams can deliver new features quicker and more effectively. What this pattern has done more than anything to date is spark organizational transformations, setting the foundation for future application development. In practice, however, there are a number of considerations to make that go beyond simply “build, ship, and run,” which changes ho...
When people aren’t talking about VMs and containers, they’re talking about serverless architecture. Serverless is about no maintenance. It means you are not worried about low-level infrastructural and operational details. An event-driven serverless platform is a great use case for IoT. In his session at @ThingsExpo, Animesh Singh, an STSM and Lead for IBM Cloud Platform and Infrastructure, will detail how to build a distributed serverless, polyglot, microservices framework using open source tec...
Gartner is now treating algorithms like they are some kind of innovative addition to the modern digital discussion. Presumably the brilliant minds there have some novel insight into algorithms and, yes, the Algorithm Economy that CIOs should sit up and take notice of. Not only are algorithms nothing new, but much of what Gartner is saying about them is obvious. The bigger picture here is that software continues to improve, and enterprises are becoming increasingly software-driven, in part bec...
The Internet of Things is clearly many things: data collection and analytics, wearables, Smart Grids and Smart Cities, the Industrial Internet, and more. Cool platforms like Arduino, Raspberry Pi, Intel's Galileo and Edison, and a diverse world of sensors are making the IoT a great toy box for developers in all these areas. In this Power Panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists discussed what things are the most important, which will have the most profound...
The Internet of Things (IoT) is growing rapidly by extending current technologies, products and networks. By 2020, Cisco estimates there will be 50 billion connected devices. Gartner has forecast revenues of over $300 billion, just to IoT suppliers. Now is the time to figure out how you’ll make money – not just create innovative products. With hundreds of new products and companies jumping into the IoT fray every month, there’s no shortage of innovation. Despite this, McKinsey/VisionMobile data...
NHK, Japan Broadcasting, will feature the upcoming @ThingsExpo Silicon Valley in a special 'Internet of Things' and smart technology documentary that will be filmed on the expo floor between November 3 to 5, 2015, in Santa Clara. NHK is the sole public TV network in Japan equivalent to the BBC in the UK and the largest in Asia with many award-winning science and technology programs. Japanese TV is producing a documentary about IoT and Smart technology and will be covering @ThingsExpo Silicon Val...
SYS-CON Events announced today that Men & Mice, the leading global provider of DNS, DHCP and IP address management overlay solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. The Men & Mice Suite overlay solution is already known for its powerful application in heterogeneous operating environments, enabling enterprises to scale without fuss. Building on a solid range of diverse platform support,...
Internet of @ThingsExpo, taking place June 7-9, 2016 at Javits Center, New York City and Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 18th International @CloudExpo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world and ThingsExpo New York Call for Papers is now open.
SYS-CON Events announced today that Catchpoint Systems, Inc., a provider of innovative web and infrastructure monitoring solutions, has been named “Silver Sponsor” of SYS-CON's DevOps Summit at 18th Cloud Expo New York, which will take place June 7-9, 2016, at the Javits Center in New York City, NY. Catchpoint is a leading Digital Performance Analytics company that provides unparalleled insight into customer-critical services to help consistently deliver an amazing customer experience. Designed...
@DevOpsSummit taking place June 7-9, 2016 at Javits Center, New York City, and Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 18th International @CloudExpo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world.
Cloud Expo, Inc. has announced today that Andi Mann returns to 'DevOps at Cloud Expo 2016' as Conference Chair The @DevOpsSummit at Cloud Expo will take place on June 7-9, 2016, at the Javits Center in New York City, New York. "DevOps is set to be one of the most profound disruptions to hit IT in decades," said Andi Mann. "It is a natural extension of cloud computing, and I have seen both firsthand and in independent research the fantastic results DevOps delivers. So I am excited to help the g...
Korean Broadcasting System (KBS) will feature the upcoming 18th Cloud Expo | @ThingsExpo in a New York news documentary about the "New IT for the Future." The documentary will cover how big companies are transmitting or adopting the new IT for the future and will be filmed on the expo floor between June 7-June 9, 2016, at the Javits Center in New York City, New York. KBS has long been a leader in the development of the broadcasting culture of Korea. As the key public service broadcaster of Korea...
SYS-CON Events announced today that Addteq will exhibit at SYS-CON's @DevOpsSummit at Cloud Expo New York, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Addteq is one of the top 10 Platinum Atlassian Experts who specialize in DevOps, custom and continuous integration, automation, plugin development, and consulting for midsize and global firms. Addteq firmly believes that automation is essential for successful software releases. Addteq centers its products a...
In the rush to compete in the digital age, a successful digital transformation is essential, but many organizations are setting themselves up for failure. There’s a common misconception that the process is just about technology, but it’s not. It’s about your business. It shouldn’t be treated as an isolated IT project; it should be driven by business needs with the committed involvement of a range of stakeholders.
SYS-CON Events announced today that FalconStor Software® Inc., a 15-year innovator of software-defined storage solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. FalconStor Software®, Inc. (NASDAQ: FALC) is a leading software-defined storage company offering a converged, hardware-agnostic, software-defined storage and data services platform. Its flagship solution FreeStor®, utilizes a horizonta...
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo 2016 in New York and Silicon Valley. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 17th Cloud Expo and will feature technical sessions from a rock star conference faculty ...
SYS-CON Events announced today that Column Technologies will exhibit at SYS-CON's @DevOpsSummit at Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Established in 1998, Column Technologies is a global technology solutions provider with over 400 employees, headquartered in the United States with offices in Canada, India, and the United Kingdom. Column Technologies provides “Best of Breed” technology solutions that automate the key DevOps principal...
SYS-CON Events announced today that SoftLayer, an IBM Company, has been named “Gold Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. SoftLayer, an IBM Company, provides cloud infrastructure as a service from a growing number of data centers and network points of presence around the world. SoftLayer’s customers range from Web startups to global enterprises.
SYS-CON Events announced today that IBM Cloud Data Services has been named “Bronze Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. IBM Cloud Data Services offers a portfolio of integrated, best-of-breed cloud data services for developers focused on mobile computing and analytics use cases.
SYS-CON Events announced today that Anexia will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Anexia offers high-quality customized managed hosting solutions for SaaS and IaaS companies. The company was founded in 2006 in Klagenfurt, Austria. Today, it has additional offices in Vienna, Graz, Munich, Cologne and New York City to serve numerous international customers.