Welcome!

Microservices Expo Authors: Pat Romanski, Dalibor Siroky, Stackify Blog, Elizabeth White, Liz McMillan

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.

@MicroservicesExpo Stories
While some developers care passionately about how data centers and clouds are architected, for most, it is only the end result that matters. To the majority of companies, technology exists to solve a business problem, and only delivers value when it is solving that problem. 2017 brings the mainstream adoption of containers for production workloads. In his session at 21st Cloud Expo, Ben McCormack, VP of Operations at Evernote, discussed how data centers of the future will be managed, how the p...
The nature of test environments is inherently temporary—you set up an environment, run through an automated test suite, and then tear down the environment. If you can reduce the cycle time for this process down to hours or minutes, then you may be able to cut your test environment budgets considerably. The impact of cloud adoption on test environments is a valuable advancement in both cost savings and agility. The on-demand model takes advantage of public cloud APIs requiring only payment for t...
It has never been a better time to be a developer! Thanks to cloud computing, deploying our applications is much easier than it used to be. How we deploy our apps continues to evolve thanks to cloud hosting, Platform-as-a-Service (PaaS), and now Function-as-a-Service. FaaS is the concept of serverless computing via serverless architectures. Software developers can leverage this to deploy an individual "function", action, or piece of business logic. They are expected to start within milliseconds...
As DevOps methodologies expand their reach across the enterprise, organizations face the daunting challenge of adapting related cloud strategies to ensure optimal alignment, from managing complexity to ensuring proper governance. How can culture, automation, legacy apps and even budget be reexamined to enable this ongoing shift within the modern software factory? In her Day 2 Keynote at @DevOpsSummit at 21st Cloud Expo, Aruna Ravichandran, VP, DevOps Solutions Marketing, CA Technologies, was jo...
You know you need the cloud, but you’re hesitant to simply dump everything at Amazon since you know that not all workloads are suitable for cloud. You know that you want the kind of ease of use and scalability that you get with public cloud, but your applications are architected in a way that makes the public cloud a non-starter. You’re looking at private cloud solutions based on hyperconverged infrastructure, but you’re concerned with the limits inherent in those technologies.
Is advanced scheduling in Kubernetes achievable?Yes, however, how do you properly accommodate every real-life scenario that a Kubernetes user might encounter? How do you leverage advanced scheduling techniques to shape and describe each scenario in easy-to-use rules and configurations? In his session at @DevOpsSummit at 21st Cloud Expo, Oleg Chunikhin, CTO at Kublr, answered these questions and demonstrated techniques for implementing advanced scheduling. For example, using spot instances and co...
The cloud era has reached the stage where it is no longer a question of whether a company should migrate, but when. Enterprises have embraced the outsourcing of where their various applications are stored and who manages them, saving significant investment along the way. Plus, the cloud has become a defining competitive edge. Companies that fail to successfully adapt risk failure. The media, of course, continues to extol the virtues of the cloud, including how easy it is to get there. Migrating...
For DevOps teams, the concepts behind service-oriented architecture (SOA) are nothing new. A style of software design initially made popular in the 1990s, SOA was an alternative to a monolithic application; essentially a collection of coarse-grained components that communicated with each other. Communication would involve either simple data passing or two or more services coordinating some activity. SOA served as a valid approach to solving many architectural problems faced by businesses, as app...
Some journey to cloud on a mission, others, a deadline. Change management is useful when migrating to public, private or hybrid cloud environments in either case. For most, stakeholder engagement peaks during the planning and post migration phases of a project. Legacy engagements are fairly direct: projects follow a linear progression of activities (the “waterfall” approach) – change managers and application coders work from the same functional and technical requirements. Enablement and develo...
Gone are the days when application development was the daunting task of the highly skilled developers backed with strong IT skills, low code application development has democratized app development and empowered a new generation of citizen developers. There was a time when app development was in the domain of people with complex coding and technical skills. We called these people by various names like programmers, coders, techies, and they usually worked in a world oblivious of the everyday pri...
From manual human effort the world is slowly paving its way to a new space where most process are getting replaced with tools and systems to improve efficiency and bring down operational costs. Automation is the next big thing and low code platforms are fueling it in a significant way. The Automation era is here. We are in the fast pace of replacing manual human efforts with machines and processes. In the world of Information Technology too, we are linking disparate systems, softwares and tool...
DevOps is good for organizations. According to the soon to be released State of DevOps Report high-performing IT organizations are 2X more likely to exceed profitability, market share, and productivity goals. But how do they do it? How do they use DevOps to drive value and differentiate their companies? We recently sat down with Nicole Forsgren, CEO and Chief Scientist at DORA (DevOps Research and Assessment) and lead investigator for the State of DevOps Report, to discuss the role of measure...
DevOps is under attack because developers don’t want to mess with infrastructure. They will happily own their code into production, but want to use platforms instead of raw automation. That’s changing the landscape that we understand as DevOps with both architecture concepts (CloudNative) and process redefinition (SRE). Rob Hirschfeld’s recent work in Kubernetes operations has led to the conclusion that containers and related platforms have changed the way we should be thinking about DevOps and...
"As we've gone out into the public cloud we've seen that over time we may have lost a few things - we've lost control, we've given up cost to a certain extent, and then security, flexibility," explained Steve Conner, VP of Sales at Cloudistics,in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
These days, APIs have become an integral part of the digital transformation journey for all enterprises. Every digital innovation story is connected to APIs . But have you ever pondered over to know what are the source of these APIs? Let me explain - APIs sources can be varied, internal or external, solving different purposes, but mostly categorized into the following two categories. Data lakes is a term used to represent disconnected but relevant data that are used by various business units wit...
With continuous delivery (CD) almost always in the spotlight, continuous integration (CI) is often left out in the cold. Indeed, it's been in use for so long and so widely, we often take the model for granted. So what is CI and how can you make the most of it? This blog is intended to answer those questions. Before we step into examining CI, we need to look back. Software developers often work in small teams and modularity, and need to integrate their changes with the rest of the project code b...
"I focus on what we are calling CAST Highlight, which is our SaaS application portfolio analysis tool. It is an extremely lightweight tool that can integrate with pretty much any build process right now," explained Andrew Siegmund, Application Migration Specialist for CAST, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
"Cloud4U builds software services that help people build DevOps platforms for cloud-based software and using our platform people can draw a picture of the system, network, software," explained Kihyeon Kim, CEO and Head of R&D at Cloud4U, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Kubernetes is an open source system for automating deployment, scaling, and management of containerized applications. Kubernetes was originally built by Google, leveraging years of experience with managing container workloads, and is now a Cloud Native Compute Foundation (CNCF) project. Kubernetes has been widely adopted by the community, supported on all major public and private cloud providers, and is gaining rapid adoption in enterprises. However, Kubernetes may seem intimidating and complex ...
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm. In their Day 3 Keynote at 20th Cloud Expo, Chris Brown, a Solutions Marketing Manager at Nutanix, and Mark Lav...