How to: Create and Bind to an ObservableCollection

This example shows how to create and bind to a collection that derives from the xref:System.Collections.ObjectModel.ObservableCollection%601 class, which is a collection class that provides notifications when items get added or removed.

Example

The following example shows the implementation of a NameList collection:

public class NameList : ObservableCollection<PersonName>  
{  
    public NameList() : base()  
    {  
        Add(new PersonName("Willa", "Cather"));  
        Add(new PersonName("Isak", "Dinesen"));  
        Add(new PersonName("Victor", "Hugo"));  
        Add(new PersonName("Jules", "Verne"));  
    }  
  }  
  
  public class PersonName  
  {  
      private string firstName;  
      private string lastName;  
  
      public PersonName(string first, string last)  
      {  
          this.firstName = first;  
          this.lastName = last;  
      }  
  
      public string FirstName  
      {  
          get { return firstName; }  
          set { firstName = value; }  
      }  
  
      public string LastName  
      {  
          get { return lastName; }  
          set { lastName = value; }  
      }  
  }

Public Class NameList  
    Inherits ObservableCollection(Of PersonName)  
  
    ' Methods  
    Public Sub New()  
        MyBase.Add(New PersonName("Willa", "Cather"))  
        MyBase.Add(New PersonName("Isak", "Dinesen"))  
        MyBase.Add(New PersonName("Victor", "Hugo"))  
        MyBase.Add(New PersonName("Jules", "Verne"))  
    End Sub  
  
End Class  
  
Public Class PersonName  
    ' Methods  
    Public Sub New(ByVal first As String, ByVal last As String)  
        Me._firstName = first  
        Me._lastName = last  
    End Sub  
  
    ' Properties  
    Public Property FirstName() As String  
        Get  
            Return Me._firstName  
        End Get  
        Set(ByVal value As String)  
            Me._firstName = value  
        End Set  
    End Property  
  
    Public Property LastName() As String  
        Get  
            Return Me._lastName  
        End Get  
        Set(ByVal value As String)  
            Me._lastName = value  
        End Set  
    End Property  
  
    ' Fields  
    Private _firstName As String  
    Private _lastName As String  
End Class

You can make the collection available for binding the same way you would with other [!INCLUDETLA#tla_clr] objects, as described in Make Data Available for Binding in XAML. For example, you can instantiate the collection in [!INCLUDETLA2#tla_xaml] and specify the collection as a resource, as shown here:

<Window  
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
  xmlns:c="clr-namespace:SDKSample"  
  x:Class="SDKSample.Window1"  
  Width="400"  
  Height="280"  
  Title="MultiBinding Sample">  
  
  <Window.Resources>  
    <c:NameList x:Key="NameListData"/>  
  
...  
  
</Window.Resources>

You can then bind to the collection:

<ListBox Width="200"  
         ItemsSource="{Binding Source={StaticResource NameListData}}"  
         ItemTemplate="{StaticResource NameItemTemplate}"  
         IsSynchronizedWithCurrentItem="True"/>

The definition of NameItemTemplate is not shown here.

[!NOTE] The objects in your collection must satisfy the requirements described in the Binding Sources Overview. In particular, if you are using xref:System.Windows.Data.BindingMode.OneWay or xref:System.Windows.Data.BindingMode.TwoWay (for example, you want your [!INCLUDETLA2#tla_ui] to update when the source properties change dynamically), you must implement a suitable property changed notification mechanism such as the xref:System.ComponentModel.INotifyPropertyChanged interface.

For more information, see the Binding to Collections section in the Data Binding Overview.

dotnet/docs

How to: Create and Bind to an ObservableCollection

Example

See Also