FrameworkElement.BindingGroup Propriedade

Definição

Obtém ou define o BindingGroup que é usado para o elemento.Gets or sets the BindingGroup that is used for the element.

public:
 property System::Windows::Data::BindingGroup ^ BindingGroup { System::Windows::Data::BindingGroup ^ get(); void set(System::Windows::Data::BindingGroup ^ value); };
[System.Windows.Localizability(System.Windows.LocalizationCategory.NeverLocalize)]
public System.Windows.Data.BindingGroup BindingGroup { get; set; }
member this.BindingGroup : System.Windows.Data.BindingGroup with get, set
Public Property BindingGroup As BindingGroup

Valor da propriedade

O BindingGroup que é usado para o elemento.The BindingGroup that is used for the element.

Atributos

Exemplos

Os exemplos a seguir fazem parte de um aplicativo que verifica se o usuário definiu as propriedades de dois objetos como valores iguais.The following examples are part of an application that checks whether the user has set the properties of two objects to equal values. O primeiro exemplo cria dois controles TextBox, cada um dos quais está associado a uma fonte de dados diferente.The first example creates two TextBox controls, each of which is bound to a different data source. O StackPanel tem uma BindingGroup que contém uma ValidationRule que verifica se as duas cadeias de caracteres são iguais.The StackPanel has a BindingGroup that contains a ValidationRule that checks that the two strings are equal.

<StackPanel>
  <StackPanel.Resources>
    <src:Type1 x:Key="object1" />
    <src:Type2 x:Key="object2" />
  </StackPanel.Resources>

  <StackPanel Name="sp1"
              Margin="5"
              DataContext="{Binding Source={StaticResource object1}}"
              Validation.ValidationAdornerSite="{Binding ElementName=label1}"
              Orientation="Horizontal"
              HorizontalAlignment="Center">

    <StackPanel.BindingGroup>
      <BindingGroup Name="bindingGroup">
        <BindingGroup.ValidationRules>
          <src:BindingGroupValidationRule ValidatesOnTargetUpdated="True" />
        </BindingGroup.ValidationRules>
      </BindingGroup>
    </StackPanel.BindingGroup>

    <TextBlock Text="First string" />

    <TextBox Width="150"
             Text="{Binding Path=PropertyA}" />

    <TextBlock Text="Second string" />

    <TextBox Width="150"
             Text="{Binding Source={StaticResource object2}, 
      Path=PropertyB, BindingGroupName=bindingGroup, 
      TargetNullValue=please enter a string}" />

  </StackPanel>

  <Label Name="label1"
         Content="{Binding ElementName=sp1, Path=(Validation.Errors)[0].ErrorContent}"
         Margin="5"
         Foreground="Red"
         HorizontalAlignment="Center" />

  <Button HorizontalAlignment="Center"
          Click="Button_Click"
          IsDefault="True">
    _Submit
  </Button>

  <StackPanel Orientation="Horizontal">
    <TextBlock Text="First string:"
               FontWeight="Bold" />
    <TextBlock Text="{Binding Source={StaticResource object1}, 
      Path=PropertyA, TargetNullValue=--}" />
  </StackPanel>

  <StackPanel Orientation="Horizontal">
    <TextBlock Text="Second string:"
               FontWeight="Bold" />
    <TextBlock Text="{Binding Source={StaticResource object2}, 
      Path=PropertyB, TargetNullValue=--}" />
  </StackPanel>
</StackPanel>

O exemplo a seguir mostra a ValidationRule que o exemplo anterior usa.The following example shows the ValidationRule that the previous example uses. Na substituição do método Validate, o exemplo obtém cada objeto de origem do BindingGroup e verifica se as propriedades dos objetos são iguais.In the Validate method override, the example gets each source object from the BindingGroup and checks whether the properties of the objects are equal.

public class Type1
{
    public string PropertyA { get; set; }

    public Type1()
    {
        PropertyA = "Default Value";
    }
}

public class Type2
{
    public string PropertyB { get; set; }

    public Type2()
    {
    }
}

public class BindingGroupValidationRule : ValidationRule
{
    public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
    {
        BindingGroup bg = value as BindingGroup;

        Type1 object1 = null;
        Type2 object2 = null;

        foreach (object item in bg.Items)
        {
            if (item is Type1)
            {
                object1 = item as Type1;
            }

            if (item is Type2)
            {
                object2 = item as Type2;
            }
        }

        if (object1 == null || object2 == null)
        {
            return new ValidationResult(false, "BindingGroup did not find source object.");
        }

        string string1 = bg.GetValue(object1, "PropertyA") as string;
        string string2 = bg.GetValue(object2, "PropertyB") as string;

        if (string1 != string2)
        {
            return new ValidationResult(false, "The two strings must be identical.");
        }

        return ValidationResult.ValidResult;

    }

}
Public Class Type1
    Public Property PropertyA() As String

    Public Sub New()
        PropertyA = "Default Value"
    End Sub
End Class

Public Class Type2
    Public Property PropertyB() As String

    Public Sub New()
    End Sub
End Class

Public Class BindingGroupValidationRule
    Inherits ValidationRule
    Public Overrides Function Validate(ByVal value As Object, ByVal cultureInfo As System.Globalization.CultureInfo) As ValidationResult
        Dim bg As BindingGroup = TryCast(value, BindingGroup)

        Dim object1 As Type1 = Nothing
        Dim object2 As Type2 = Nothing

        For Each item As Object In bg.Items
            If TypeOf item Is Type1 Then
                object1 = TryCast(item, Type1)
            End If

            If TypeOf item Is Type2 Then
                object2 = TryCast(item, Type2)
            End If
        Next item

        If object1 Is Nothing OrElse object2 Is Nothing Then
            Return New ValidationResult(False, "BindingGroup did not find source object.")
        End If

        Dim string1 As String = TryCast(bg.GetValue(object1, "PropertyA"), String)
        Dim string2 As String = TryCast(bg.GetValue(object2, "PropertyB"), String)

        If string1 <> string2 Then
            Return New ValidationResult(False, "The two strings must be identical.")
        End If

        Return ValidationResult.ValidResult

    End Function

End Class

Para invocar o ValidationRule, chame o método UpdateSources.To invoke the ValidationRule, call the UpdateSources method. O exemplo a seguir chama UpdateSources quando o evento de clique do botão ocorre.The following example calls UpdateSources when the click event of the button occurs.

private void Button_Click(object sender, RoutedEventArgs e)
{
    sp1.BindingGroup.UpdateSources();
}
Private Sub Button_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    sp1.BindingGroup.UpdateSources()
End Sub

Comentários

Um BindingGroup pode ser usado para validar os valores de várias propriedades de um objeto.A BindingGroup can be used to validate the values of multiple properties of an object. Por exemplo, suponha que um aplicativo solicite que o usuário insira um endereço e, em seguida, preencha um objeto do tipo Address, que tem as propriedades Street, City, ZipCodee Country, com os valores fornecidos pelo usuário.For example, suppose that an application prompts the user to enter an address and then populates an object of type Address, which has the properties Street, City, ZipCode, and Country, with the values that the user provided. O aplicativo tem um painel que contém quatro controles de TextBox, cada um dos quais está associado a uma das propriedades do objeto.The application has a panel that contains four TextBox controls, each of which is bound to one of the object's properties. Você pode usar um ValidationRule em uma BindingGroup para validar o objeto Address.You can use a ValidationRule in a BindingGroup to validate the Address object. Por exemplo, o ValidationRule pode garantir que o CEP seja válido para o país/região do endereço.For example, the ValidationRule can ensure that the zip code is valid for the country/region of the address.

Os elementos filho herdam os BindingGroup de seus elementos pai, assim como com qualquer outra propriedade herdável.Child elements inherit the BindingGroup from their parent elements, just as with any other inheritable property.

Informações de Propriedade de DependênciaDependency Property Information

Campo de identificadorIdentifier field BindingGroupProperty
Propriedades de metadados definidas como trueMetadata properties set to true Inherits

Aplica-se a