Como: Create and Bind to an ObservableCollection

This example shows how to create and bind to a collection that derives from the ObservableCollection<T> class, which is a collection class that provides notifications when items get added or removed.

Exemplo

The following example shows the implementation of a NameList collection:

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

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; }
      }
  }

Você pode disponibilizar a coleção de ligação da mesma forma que faria com os outros common language runtime (CLR) objetos, conforme descrito em Como: Make Data Available for Binding in XAML. For example, you can instantiate the collection in XAML and specify the collection as a resource, as shown here:

<Window
  xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="https://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.

Observação

The objects in your collection must satisfy the requirements described in the Visão geral sobre associação de fontes.In particular, if you are using OneWay or TwoWay (for example, you want your UI to update when the source properties change dynamically), you must implement a suitable property changed notification mechanism such as the INotifyPropertyChanged interface.

For more information, see the Binding to Collections section in the Revisão de Associação de Dados.

Consulte também

Tarefas

Como: Sort Data in a View

Como: Filtrar dados em um modo de exibição

Como: Ordenar e Agrupar Dados usando um modo de exibição em XAML

Conceitos

Revisão de Associação de Dados

Outros recursos

Data Binding How-to Topics