FrameworkElement.ActualHeight Propriedade

Definição

Obtém a altura renderizada desse elemento.Gets the rendered height of this element.

public:
 property double ActualHeight { double get(); };
public double ActualHeight { get; }
member this.ActualHeight : double
Public ReadOnly Property ActualHeight As Double

Valor da propriedade

A altura do elemento, como um valor em unidades independentes de dispositivo (1/96 polegada por unidade)device-independent units (1/96th inch per unit).The element's height, as a value in unidades independentes de dispositivo (1/96 polegada por unidade)device-independent units (1/96th inch per unit). O valor padrão é 0 (zero).The default value is 0 (zero).

Exemplos

O exemplo a seguir exibe várias propriedades de altura.The following example displays various height properties.

private void changeHeight(object sender, SelectionChangedEventArgs args)
{
    ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem);
    Double sz1 = Double.Parse(li.Content.ToString());
    rect1.Height = sz1;
    rect1.UpdateLayout();
    txt1.Text= "ActualHeight is set to " + rect1.ActualHeight;
    txt2.Text= "Height is set to " + rect1.Height;
    txt3.Text= "MinHeight is set to " + rect1.MinHeight;
    txt4.Text= "MaxHeight is set to " + rect1.MaxHeight;
}
private void changeMinHeight(object sender, SelectionChangedEventArgs args)
{
    ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem);
    Double sz1 = Double.Parse(li.Content.ToString());
    rect1.MinHeight = sz1;
    rect1.UpdateLayout();
    txt1.Text= "ActualHeight is set to " + rect1.ActualHeight;
    txt2.Text= "Height is set to " + rect1.Height;
    txt3.Text= "MinHeight is set to " + rect1.MinHeight;
    txt4.Text= "MaxHeight is set to " + rect1.MaxHeight;
}
private void changeMaxHeight(object sender, SelectionChangedEventArgs args)
{
    ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem);
    Double sz1 = Double.Parse(li.Content.ToString());
    rect1.MaxHeight = sz1;
    rect1.UpdateLayout();
    txt1.Text= "ActualHeight is set to " + rect1.ActualHeight;
    txt2.Text= "Height is set to " + rect1.Height;
    txt3.Text= "MinHeight is set to " + rect1.MinHeight;
    txt4.Text= "MaxHeight is set to " + rect1.MaxHeight;
}
Private Sub changeHeight(ByVal sender As Object, ByVal args As SelectionChangedEventArgs)
    Dim li As ListBoxItem = CType(CType(sender, ListBox).SelectedItem, ListBoxItem)
    Dim sz1 As Double = Double.Parse(li.Content.ToString())
    rect1.Height = sz1
    rect1.UpdateLayout()
    txt1.Text = "ActualHeight is set to " + rect1.ActualHeight.ToString
    txt2.Text = "Height is set to " + rect1.Height.ToString
    txt3.Text = "MinHeight is set to " + rect1.MinHeight.ToString
    txt4.Text = "MaxHeight is set to " + rect1.MaxHeight.ToString
End Sub
Private Sub changeMinHeight(ByVal sender As Object, ByVal args As SelectionChangedEventArgs)

    Dim li As ListBoxItem = CType(CType(sender, ListBox).SelectedItem, ListBoxItem)
    Dim sz1 As Double = Double.Parse(li.Content.ToString())
    rect1.MinHeight = sz1
    rect1.UpdateLayout()
    txt1.Text = "ActualHeight is set to " + rect1.ActualHeight.ToString
    txt2.Text = "Height is set to " + rect1.Height.ToString
    txt3.Text = "MinHeight is set to " + rect1.MinHeight.ToString
    txt4.Text = "MaxHeight is set to " + rect1.MaxHeight.ToString
End Sub
Private Sub changeMaxHeight(ByVal sender As Object, ByVal args As SelectionChangedEventArgs)

    Dim li As ListBoxItem = CType(CType(sender, ListBox).SelectedItem, ListBoxItem)
    Dim sz1 As Double = Double.Parse(li.Content.ToString())
    rect1.MaxHeight = sz1
    rect1.UpdateLayout()
    txt1.Text = "ActualHeight is set to " + rect1.ActualHeight.ToString
    txt2.Text = "Height is set to " + rect1.Height.ToString
    txt3.Text = "MinHeight is set to " + rect1.MinHeight.ToString
    txt4.Text = "MaxHeight is set to " + rect1.MaxHeight.ToString
End Sub

Comentários

Essa propriedade é um valor calculado com base em outras entradas de altura e no sistema de layout.This property is a calculated value based on other height inputs, and the layout system. O valor é definido pelo próprio sistema de layout, com base em uma passagem de renderização real, e, portanto, pode atrasar ligeiramente por trás do valor definido das propriedades, como Height que são a base da alteração de entrada.The value is set by the layout system itself, based on an actual rendering pass, and may therefore lag slightly behind the set value of properties such as Height that are the basis of the input change.

Como ActualHeight é um valor calculado, você deve estar ciente de que pode haver várias alterações relatadas e incrementadas nele como resultado de várias operações pelo sistema de layout.Because ActualHeight is a calculated value, you should be aware that there could be multiple or incremental reported changes to it as a result of various operations by the layout system. O sistema de layout pode estar calculando o espaço de medição necessário para elementos filhos, as restrições do elemento pai e assim por diante.The layout system may be calculating required measure space for child elements, constraints by the parent element, and so on.

Embora não seja possível definir essa propriedade de XAMLXAML, você pode basear uma Trigger após seu valor em um estilo.Although you cannot set this property from XAMLXAML, you can base a Trigger upon its value in a style.

Informações de Propriedade de DependênciaDependency Property Information

Campo de identificadorIdentifier field ActualHeightProperty
Propriedades de metadados definidas como trueMetadata properties set to true NenhumNone

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