Export (0) Print
Expand All
This topic has not yet been rated - Rate this topic

FrameworkElement.VisualChildrenCount Property

Gets the number of visual child elements within this element.

Namespace:  System.Windows
Assembly:  PresentationFramework (in PresentationFramework.dll)
protected override int VisualChildrenCount { get; }

Property Value

Type: System.Int32
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).

Notes to Inheritors

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]; }

.NET Framework

Supported in: 4.5.1, 4.5, 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Show:
© 2014 Microsoft. All rights reserved.