Track.ViewportSize Property

Gets or sets the size of the part of the scrollable content that is visible.

Namespace: System.Windows.Controls.Primitives
Assembly: PresentationFramework (in presentationframework.dll)
XML Namespace:

public double ViewportSize { get; set; }
/** @property */
public double get_ViewportSize ()

/** @property */
public void set_ViewportSize (double value)

public function get ViewportSize () : double

public function set ViewportSize (value : double)

<object ViewportSize="double" .../>

Property Value

The size of the visible area of the scrollable content. The default value is Double.NaN, which means that the content size is not defined.

The value of the ViewportSize property is used to calculate the size of the Thumb control in a ScrollBar when the ViewportSize is not Double.NaN. For more information, see the remarks for the Thumb property.

To explicitly define the size of the Thumb, create an object that derives from the Track class and provide overrides for MeasureOverride and ArrangeOverride.

If you implement a Track as part of a ScrollBar control and you do not explicitly set the ViewportSize property, the ViewportSize property binds to the ViewportSize property.

The value of the ViewportSize property of a Track control that is implemented in a Slider control is always Double.NaN, because the Thumb control does not change size.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0

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