DataServiceCollection(T) Class (System.Data.Services.Client)

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DataServiceCollection<T> Class

Represents a dynamic entity collection that provides notifications when items get added, removed, or when the list is refreshed.

Inheritance Hierarchy

System.Object
  System.Collections.ObjectModel.Collection<T>
    System.Collections.ObjectModel.ObservableCollection<T>
      System.Data.Services.Client.DataServiceCollection<T>

Namespace:  System.Data.Services.Client
Assembly:  System.Data.Services.Client (in System.Data.Services.Client.dll)
Syntax

Visual Basic
Public Class DataServiceCollection(Of T) _
	Inherits ObservableCollection(Of T)
C#
public class DataServiceCollection<T> : ObservableCollection<T>

Visual C++
generic<typename T>
public ref class DataServiceCollection : public ObservableCollection<T>
F#
type DataServiceCollection<'T> =  
    class
        inherit ObservableCollection<'T>
    end

Type Parameters

T

An entity type.

The DataServiceCollection<T> type exposes the following members.

Constructors

  Name Description
Public method DataServiceCollection<T>() Creates a new instance of the DataServiceCollection<T> class.
Public method DataServiceCollection<T>(DataServiceContext) Creates a new instance of the DataServiceCollection<T> class that uses the specified DataServiceContext.
Public method DataServiceCollection<T>(IEnumerable<T>) Creates a new instance of the DataServiceCollection<T> class based on query execution.
Public method DataServiceCollection<T>(IEnumerable<T>, TrackingMode) Creates a new instance of the DataServiceCollection<T> class based on query execution and with the specified tracking mode.
Public method DataServiceCollection<T>(DataServiceContext, String, Func<EntityChangedParams, Boolean>, Func<EntityCollectionChangedParams, Boolean>) Creates a new instance of the DataServiceCollection<T> class with the supplied change method delegates and that uses the specified DataServiceContext.
Public method DataServiceCollection<T>(IEnumerable<T>, TrackingMode, String, Func<EntityChangedParams, Boolean>, Func<EntityCollectionChangedParams, Boolean>) Creates a new instance of the DataServiceCollection<T> class a based on query execution and with the supplied change method delegates.
Public method DataServiceCollection<T>(DataServiceContext, IEnumerable<T>, TrackingMode, String, Func<EntityChangedParams, Boolean>, Func<EntityCollectionChangedParams, Boolean>) Creates a new instance of the DataServiceCollection<T> class a based on query execution, with the supplied change method delegates, and that uses the supplied DataServiceContext.
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Properties

  Name Description
Public property Continuation Gets a continuation object that is used to return the next set of paged results.
Public property Count Gets the number of elements actually contained in the Collection<T>. (Inherited from Collection<T>.)
Public property Item Gets or sets the element at the specified index. (Inherited from Collection<T>.)
Protected property Items Gets a IList<T> wrapper around the Collection<T>. (Inherited from Collection<T>.)
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Methods

  Name Description
Public method Add Adds an object to the end of the Collection<T>. (Inherited from Collection<T>.)
Protected method BlockReentrancy Disallows reentrant attempts to change this collection. (Inherited from ObservableCollection<T>.)
Protected method CheckReentrancy Checks for reentrant attempts to change this collection. (Inherited from ObservableCollection<T>.)
Public method Clear() Removes all elements from the Collection<T>. (Inherited from Collection<T>.)
Public method Clear(Boolean) Removes all items from the collection, and optionally detaches all the items from the DataServiceContext.
Protected method ClearItems Removes all items from the collection. (Inherited from ObservableCollection<T>.)
Public method Contains Determines whether an element is in the Collection<T>. (Inherited from Collection<T>.)
Public method CopyTo Copies the entire Collection<T> to a compatible one-dimensional Array, starting at the specified index of the target array. (Inherited from Collection<T>.)
Public method Detach Disables DataServiceContext tracking of all items in the collection.
Public method Equals(Object) Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected method Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method GetEnumerator Returns an enumerator that iterates through the Collection<T>. (Inherited from Collection<T>.)
Public method GetHashCode Serves as a hash function for a particular type. (Inherited from Object.)
Public method GetType Gets the Type of the current instance. (Inherited from Object.)
Public method IndexOf Searches for the specified object and returns the zero-based index of the first occurrence within the entire Collection<T>. (Inherited from Collection<T>.)
Public method Insert Inserts an element into the Collection<T> at the specified index. (Inherited from Collection<T>.)
Protected method InsertItem Adds a specified item to the collection at the specified index. (Overrides ObservableCollection<T>.InsertItem(Int32, T).)
Public method Load(T) Loads a single entity object into the collection.
Public method Load(IEnumerable<T>) Loads a collection of entity objects into the collection.
Protected method MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method Move Moves the item at the specified index to a new location in the collection. (Inherited from ObservableCollection<T>.)
Protected method MoveItem Moves the item at the specified index to a new location in the collection. (Inherited from ObservableCollection<T>.)
Protected method OnCollectionChanged Raises the CollectionChanged event with the provided arguments. (Inherited from ObservableCollection<T>.)
Protected method OnPropertyChanged Raises the PropertyChanged event with the provided arguments. (Inherited from ObservableCollection<T>.)
Public method Remove Removes the first occurrence of a specific object from the Collection<T>. (Inherited from Collection<T>.)
Public method RemoveAt Removes the element at the specified index of the Collection<T>. (Inherited from Collection<T>.)
Protected method RemoveItem Removes the item at the specified index of the collection. (Inherited from ObservableCollection<T>.)
Protected method SetItem Replaces the element at the specified index. (Inherited from ObservableCollection<T>.)
Public method ToString Returns a string that represents the current object. (Inherited from Object.)
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Events

  Name Description
Public event CollectionChanged Occurs when an item is added, removed, changed, moved, or the entire list is refreshed. (Inherited from ObservableCollection<T>.)
Protected event PropertyChanged Occurs when a property value changes. (Inherited from ObservableCollection<T>.)
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Explicit Interface Implementations

  Name Description
Explicit interface implemetation Private method ICollection.CopyTo Copies the elements of the ICollection to an Array, starting at a particular Array index. (Inherited from Collection<T>.)
Explicit interface implemetation Private property ICollection<T>.IsReadOnly Gets a value indicating whether the ICollection<T> is read-only. (Inherited from Collection<T>.)
Explicit interface implemetation Private property ICollection.IsSynchronized Gets a value indicating whether access to the ICollection is synchronized (thread safe). (Inherited from Collection<T>.)
Explicit interface implemetation Private property ICollection.SyncRoot Gets an object that can be used to synchronize access to the ICollection. (Inherited from Collection<T>.)
Explicit interface implemetation Private method IEnumerable.GetEnumerator Returns an enumerator that iterates through a collection. (Inherited from Collection<T>.)
Explicit interface implemetation Private method IList.Add Adds an item to the IList. (Inherited from Collection<T>.)
Explicit interface implemetation Private method IList.Contains Determines whether the IList contains a specific value. (Inherited from Collection<T>.)
Explicit interface implemetation Private method IList.IndexOf Determines the index of a specific item in the IList. (Inherited from Collection<T>.)
Explicit interface implemetation Private method IList.Insert Inserts an item into the IList at the specified index. (Inherited from Collection<T>.)
Explicit interface implemetation Private property IList.IsFixedSize Gets a value indicating whether the IList has a fixed size. (Inherited from Collection<T>.)
Explicit interface implemetation Private property IList.IsReadOnly Gets a value indicating whether the IList is read-only. (Inherited from Collection<T>.)
Explicit interface implemetation Private property IList.Item Gets or sets the element at the specified index. (Inherited from Collection<T>.)
Explicit interface implemetation Private method IList.Remove Removes the first occurrence of a specific object from the IList. (Inherited from Collection<T>.)
Explicit interface implemetation Private event INotifyPropertyChanged.PropertyChanged Occurs when a property value changes. (Inherited from ObservableCollection<T>.)
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Remarks

WCF Data Services provides the DataServiceCollection<T> class to support binding data to controls in client applications. This class inherits from the ObservableCollection<T> class, which implements the INotifyCollectionChanged interface and is the primary data binding mechanism for Windows Presentation Foundation (WPF) and Silverlight-based applications.

You can load an ObservableCollection<T> binding collection by using any collection that implements the IEnumerable<T> interface. Items loaded into the binding collection must implement the INotifyPropertyChanged interface. For more information, see Binding Data to Controls (WCF Data Services).

Examples

The following example is from the code-behind page for an Extensible Application Markup Language (XAML) page that defines the SalesOrders window in WPF. When the window is loaded, an DataServiceCollection<T> is created based on the result of a query that returns customers with related objects, filtered by country. This result is bound to the DataContext property of the StackPanel that is the root layout control for the WPF window.

Visual Basic

Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Text
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Data
Imports System.Windows.Documents
Imports System.Windows.Input
Imports System.Windows.Media
Imports System.Windows.Media.Imaging
Imports System.Windows.Navigation
Imports System.Windows.Shapes
Imports System.Data.Services.Client
Imports NorthwindClient.Northwind

Partial Public Class CustomerOrdersWpf
    Inherits Window

    Private context As NorthwindEntities
    Private trackedCustomers As DataServiceCollection(Of Customer)
    Private Const customerCountry As String = "Germany"
    Private Const svcUri As String = "http://localhost:12345/Northwind.svc/"
    Private Sub Window_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)
        Try
            ' Initialize the context for the data service.
            context = New NorthwindEntities(New Uri(svcUri))

            ' Create a LINQ query that returns customers with related orders.
            Dim customerQuery = From cust In context.Customers.Expand("Orders") _
                                    Where cust.Country = customerCountry _
                                    Select cust

                ' Create a new collection for binding based on the LINQ query.
            trackedCustomers = New DataServiceCollection(Of Customer)(customerQuery)

                ' Bind the root StackPanel element to the collection
                ' related object binding paths are defined in the XAML.
            Me.LayoutRoot.DataContext = trackedCustomers
        Catch ex As DataServiceQueryException
            MessageBox.Show("The query could not be completed:\n" + ex.ToString())
        Catch ex As InvalidOperationException
            MessageBox.Show("The following error occurred:\n" + ex.ToString())
        End Try
    End Sub
    Private Sub saveChangesButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
        ' Save changes to the data service.
        context.SaveChanges()
    End Sub
End Class


C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Data.Services.Client;
using NorthwindClient.Northwind;

namespace NorthwindClient
{
    public partial class CustomerOrdersWpf : Window
    {
        private NorthwindEntities context;
        private DataServiceCollection<Customer> trackedCustomers;
        private const string customerCountry = "Germany";
        private const string svcUri = "http://localhost:12345/Northwind.svc/";

        public CustomerOrdersWpf()
        {
            InitializeComponent();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            try
            {
                // Initialize the context for the data service.
                context = new NorthwindEntities(new Uri(svcUri));

                // Create a LINQ query that returns customers with related orders.
                var customerQuery = from cust in context.Customers.Expand("Orders")
                                    where cust.Country == customerCountry
                                    select cust;

                // Create a new collection for binding based on the LINQ query.
                trackedCustomers = new DataServiceCollection<Customer>(customerQuery);

                // Bind the root StackPanel element to the collection;
                // related object binding paths are defined in the XAML.
                LayoutRoot.DataContext = trackedCustomers;
            }
            catch (DataServiceQueryException ex)
            {
                MessageBox.Show("The query could not be completed:\n" + ex.ToString());
            }
            catch (InvalidOperationException ex)
            {
                MessageBox.Show("The following error occurred:\n" + ex.ToString());
            }
        }
        private void saveChangesButton_Click(object sender, RoutedEventArgs e)
        {
            // Save changes to the data service.
            context.SaveChanges();
        }
    }
}


The following is the XAML that defines the SalesOrders window in WPF for the previous example.

XAML

    <Window x:Class="CustomerOrdersWpf"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             Height="423" Width="679" Loaded="Window_Loaded">
    <StackPanel Orientation="Vertical" Height="Auto" Name="LayoutRoot" Width="Auto">
        <Label Content="Customer ID" Margin="20,0,0,0" />
        <ComboBox Name="customerIDComboBox" DisplayMemberPath="CustomerID" ItemsSource="{Binding}" 
                  IsSynchronizedWithCurrentItem="True" SelectedIndex="0" Height="23" Width="120" 
                  HorizontalAlignment="Left" Margin="20,0,0,0" VerticalAlignment="Center" />
        <ListView ItemsSource="{Binding Path=Orders}" Name="ordersDataGrid" Margin="34,46,34,50">
            <ListView.View>
                <GridView AllowsColumnReorder="False" ColumnHeaderToolTip="Line Items">
                    <GridViewColumn DisplayMemberBinding="{Binding Path=OrderID, Mode=OneWay}" 
                        Header="Order ID" Width="50"/>
                    <GridViewColumn DisplayMemberBinding="{Binding Path=OrderDate, Mode=TwoWay}" 
                        Header="Order Date" Width="50"/>
                    <GridViewColumn DisplayMemberBinding="{Binding Path=Freight, Mode=TwoWay}" 
                        Header="Freight Cost" Width="50"/>
                </GridView>
            </ListView.View>
        </ListView>
        <Button Name="saveChangesButton" Content="Save Changes" Click="saveChangesButton_Click" 
                Width="80" Height="30" Margin="450,0,0,0"/>
    </StackPanel>
</Window>


Version Information

.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
See Also

Reference

Other Resources