VirtualizingStackPanel.ViewportWidth Property    
Definition
Important
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Gets a value that contains the horizontal size of the viewport of the content.
public:
 property double ViewportWidth { double get(); };public double ViewportWidth { get; }member this.ViewportWidth : doublePublic ReadOnly Property ViewportWidth As DoubleProperty Value
A Double that represents the vertical size of the viewport of the content. The default is 0.0.