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FrameworkElement.VisualChildrenCount, propriété

Gets the number of visual child elements within this element.

Espace de noms: System.Windows
Assembly : PresentationFramework (dans presentationframework.dll)
Espace de noms XML :  http://schemas.microsoft.com/winfx/2006/xaml/presentation

protected override int VisualChildrenCount { get; }
/** @property */
protected int get_VisualChildrenCount ()

protected override function get VisualChildrenCount () : int

Vous ne pouvez pas utiliser cette propriété dans XAML.

Valeur de la propriété

The number of visual child elements for this element.

The FrameworkElement implementation of VisualChildrenCount always returns either zero or one. Classes that maintain a visual child collection that might exceed one must override both this property and GetVisualChild.

This property is generally used to determine the upper bounds of the current child collection for purposes of implementing the layout overrides (MeasureOverride, ArrangeOverride).

Remarques à l'attention des héritiers : If your class supports more than one visual child in a child element collection, override this property to return the count of elements in that collection. You must do this even if the collection object itself returns a count. Element layout logic at the WPF framework level presumes that all elements will return a valid count through their VisualChildrenCount property.

The following example shows how a custom adorner uses the values declared by a VisualCollection that it maintains for its multiple visual children and reports these values through overrides of VisualChildrenCount and GetVisualChild.

    // To store and manage the adorner's visual children.
    VisualCollection visualChildren;
...

    // Override the VisualChildrenCount and GetVisualChild properties to interface with 
    // the adorner's visual collection.
    protected override int VisualChildrenCount { get { return visualChildren.Count; } }
    protected override Visual GetVisualChild(int index) { return visualChildren[index]; }

Microsoft .NET Framework 3.0 est pris en charge sur Windows Vista, Microsoft Windows XP SP2 et Windows Server 2003 SP1.

.NET Framework

Prise en charge dans : 3.0

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