Accessing Sharepoint Online lists using Silverlight 5?

Question

I'm developing an application using Silverlight 5, Visual Studio 2010 and VB.Net.

I've reached the stage where I have a requirement to read and write information to a Sharepoint Online list, but I'm really struggling to get my head round how I should do this.

There seem to be at couple least a couple of methods:

1. Using Lists.asmx - I have added this as a Service Reference, but it doesn't seems to have made available some methods (?) I would expect to see. i.e. intellisense sees lots of GetListItems* methods, but not plain old GetList. Where am I going wrong?

2. Alternatively, I think I can install the Silverlight Client Object for Sharepoint 2010 and use this? But again I'm not really sure where to start.

Can anybody advise me as to which way I should be leaning, and perhaps give me pointers to start me off.

Thanks,

JT

Answer 1

Ok first you need to configure SharePoint Foundation 2010 for your development machine so you can have the Silverlight 5 SharePoint Client Object Model you can find that here.

http://msdn.microsoft.com/en-us/library/ee554869.aspx

Next after you have completed that use the below link on how to use the Silverlight OM.

http://msdn.microsoft.com/en-us/library/ee538971.aspx

Below is sample code

    Imports System
    Imports System.Collections.Generic
    Imports System.Linq
    Imports System.Net
     Imports System.Windows
    Imports System.Windows.Controls
    Imports System.Windows.Documents
    Imports System.Windows.Input
    Imports System.Windows.Media
    Imports System.Windows.Media.Animation
    Imports System.Windows.Shapes
    Imports Microsoft.SharePoint.Client

    Namespace Microsoft.SDK.SharePointServices.Samples
Partial Public Class MainPage
    Inherits UserControl
    Private oWebsite As Web
    Private collList As ListCollection
    Private listInfo As IEnumerable(Of List)

    Public Sub New()
        InitializeComponent()
    End Sub

    Private Sub Button_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
        Dim clientContext As ClientContext = ClientContext.Current
        oWebsite = clientContext.Web
        Dim collList As ListCollection = oWebsite.Lists

        clientContext.Load(oWebsite, Function(website) website.Title)

        listInfo = clientContext.LoadQuery(collList.Include(Function(list) list.Title, Function(list) list.Fields.Include(Function(field) field.Title).Where(Function(field) field.Required = True AndAlso field.Hidden <> True)))

        clientContext.ExecuteQueryAsync(AddressOf onQuerySucceeded, AddressOf onQueryFailed)
    End Sub

    Private Sub onQuerySucceeded(ByVal sender As Object, ByVal args As ClientRequestSucceededEventArgs)
        Dim updateUI As UpdateUIMethod = AddressOf DisplayInfo
        Me.Dispatcher.BeginInvoke(updateUI)
    End Sub

    Private Sub onQueryFailed(ByVal sender As Object, ByVal args As ClientRequestFailedEventArgs)
        MessageBox.Show = "Request failed. " & args.Message & vbLf & args.StackTrace
    End Sub

    Private Sub DisplayInfo()
        MyOutput.Text = "Title: " & oWebsite.Title
        collList = oWebsite.Lists

        For Each oList As List In listInfo
            MyOutput.Text += vbLf & vbTab & "List: " & oList.Title

            Dim collField As FieldCollection = oList.Fields
            For Each oField As Field In collField
                MyOutput.Text += vbLf & vbTab & vbTab & "Field: " & oField.Title
            Next oField
        Next oList
    End Sub

    Private Delegate Sub UpdateUIMethod()
End Class
End Namespace

EDIT:

One more Important Detail about the ClientContext. If you use ClientContext.Current your silverlight application has to be ran within a silverlight web part to work. To access a specific site instantiate your context like below.

     Private ReadOnly Property ClientCtxt As Microsoft.SharePoint.Client.ClientContext
    Get
        If clientContext Is Nothing Then
            ' clientContext = New ClientContext("http://1mem8400:25775/FTP/Engineering/NPI")
            clientContext = Microsoft.SharePoint.Client.ClientContext.Current
        End If
        If clientContext Is Nothing Then
            Throw New Exception("SharePoint Connection Failed")
        End If
        Return clientContext
    End Get
End Property