Colin Eberhardt created a very useful Clipping behavior class which helps you do clipping easily. The behavior can detect the ActualHeight and ActualWidth at run time and create a RectangleGeometry() to Clip your Grid.
c# implementation of the behavior:
using System;
using System.Windows;
namespace Namespace
{
public class Clip
{
public static bool GetToBounds(DependencyObject depObj)
{
return (bool)depObj.GetValue(ToBoundsProperty);
}
public static void SetToBounds(DependencyObject depObj, bool clipToBounds)
{
depObj.SetValue(ToBoundsProperty, clipToBounds);
}
/// <summary>
/// Identifies the ToBounds Dependency Property.
/// <summary>
public static readonly DependencyProperty ToBoundsProperty =
DependencyProperty.RegisterAttached("ToBounds", typeof(bool),
typeof(Clip), new PropertyMetadata(false, OnToBoundsPropertyChanged));
private static void OnToBoundsPropertyChanged(DependencyObject d,
DependencyPropertyChangedEventArgs e)
{
FrameworkElement fe = d as FrameworkElement;
if (fe != null)
{
ClipToBounds(fe);
// whenever the element which this property is attached to is loaded
// or re-sizes, we need to update its clipping geometry
fe.Loaded += new RoutedEventHandler(fe_Loaded);
fe.SizeChanged += new SizeChangedEventHandler(fe_SizeChanged);
}
}
/// <summary>
/// Creates a rectangular clipping geometry which matches the geometry of the
/// passed element
/// </summary>
private static void ClipToBounds(FrameworkElement fe)
{
if (GetToBounds(fe))
{
fe.Clip = new RectangleGeometry()
{
Rect = new Rect(0, 0, fe.ActualWidth, fe.ActualHeight)
};
}
else
{
fe.Clip = null;
}
}
static void fe_SizeChanged(object sender, SizeChangedEventArgs e)
{
ClipToBounds(sender as FrameworkElement);
}
static void fe_Loaded(object sender, RoutedEventArgs e)
{
ClipToBounds(sender as FrameworkElement);
}
}
}
sample usage in XAML:
<UserControl x:Class="Namespace.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:this="clr-namespace:Namespace;assembly=Namespace"
>
<Grid x:Name="LayoutRoot" this:Clip.ToBounds="True" >
</Grid>
</UserControl>
