FrameworkElement.ActualWidth 屬性

定義

取得呈現此項目的寬度。Gets the rendered width of this element.

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

屬性值

項目的寬度,做為裝置獨立單位 (每單位 1/96 英吋)device-independent units (1/96th inch per unit) 內的值。The element's width, as a value in 裝置獨立單位 (每單位 1/96 英吋)device-independent units (1/96th inch per unit). 預設值為 0 (零)。The default value is 0 (zero).

範例

下列範例會顯示各種寬度屬性。The following example displays various width properties.

private void changeWidth(object sender, SelectionChangedEventArgs args)
{
    ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem);
    Double sz1 = Double.Parse(li.Content.ToString());
    rect1.Width = sz1;
    rect1.UpdateLayout();
    txt1.Text = "ActualWidth is set to " + rect1.ActualWidth;
    txt2.Text = "Width is set to " + rect1.Width;
    txt3.Text = "MinWidth is set to " + rect1.MinWidth;
    txt4.Text = "MaxWidth is set to " + rect1.MaxWidth;
}
private void changeMinWidth(object sender, SelectionChangedEventArgs args)
{
    ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem);
    Double sz1 = Double.Parse(li.Content.ToString());
    rect1.MinWidth = sz1;
    rect1.UpdateLayout();
    txt1.Text = "ActualWidth is set to " + rect1.ActualWidth;
    txt2.Text = "Width is set to " + rect1.Width;
    txt3.Text = "MinWidth is set to " + rect1.MinWidth;
    txt4.Text = "MaxWidth is set to " + rect1.MaxWidth;
}
private void changeMaxWidth(object sender, SelectionChangedEventArgs args)
{
    ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem);
    Double sz1 = Double.Parse(li.Content.ToString());
    rect1.MaxWidth = sz1;
    rect1.UpdateLayout();
    txt1.Text = "ActualWidth is set to " + rect1.ActualWidth;
    txt2.Text = "Width is set to " + rect1.Width;
    txt3.Text = "MinWidth is set to " + rect1.MinWidth;
    txt4.Text = "MaxWidth is set to " + rect1.MaxWidth;
}
Private Sub changeWidth(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.Width = sz1
    rect1.UpdateLayout()
    txt1.Text = "ActualWidth is set to " + rect1.ActualWidth.ToString
    txt2.Text = "Width is set to " + rect1.Width.ToString
    txt3.Text = "MinWidth is set to " + rect1.MinWidth.ToString
    txt4.Text = "MaxWidth is set to " + rect1.MaxWidth.ToString
End Sub
Private Sub changeMinWidth(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.MinWidth = sz1
    rect1.UpdateLayout()
    txt1.Text = "ActualWidth is set to " + rect1.ActualWidth.ToString
    txt2.Text = "Width is set to " + rect1.Width.ToString
    txt3.Text = "MinWidth is set to " + rect1.MinWidth.ToString
    txt4.Text = "MaxWidth is set to " + rect1.MaxWidth.ToString
End Sub
Private Sub changeMaxWidth(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.MaxWidth = sz1
    rect1.UpdateLayout()
    txt1.Text = "ActualWidth is set to " + rect1.ActualWidth.ToString
    txt2.Text = "Width is set to " + rect1.Width.ToString
    txt3.Text = "MinWidth is set to " + rect1.MinWidth.ToString
    txt4.Text = "MaxWidth is set to " + rect1.MaxWidth.ToString
End Sub

備註

此屬性是以其他寬度輸入和版面配置系統為基礎的計算值。This property is a calculated value based on other width inputs, and the layout system. 根據實際的轉譯行程,此值是由配置系統本身設定,因此可能會稍微落後屬性的設定值,例如輸入變更基礎的 WidthThe 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 Width that are the basis of the input change.

因為 ActualWidth 是一個計算值,所以您應該注意到它可能會因為配置系統的各種作業而產生多個或累加式的報告變更。Because ActualWidth 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. 配置系統可能會計算子項目所需的測量空間、父項目的條件約束,依此類推。The layout system may be calculating required measure space for child elements, constraints by the parent element, and so on.

雖然您無法從 XAMLXAML設定這個屬性,但您可以根據樣式中的值,以 Trigger 為基礎。Although you cannot set this property from XAMLXAML, you can base a Trigger upon its value in a style.

相依性屬性資訊Dependency Property Information

識別碼欄位Identifier field ActualWidthProperty
設定為 true 的中繼資料屬性Metadata properties set to true None

適用於