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Silverlight/WPF tip 4 : Issue with styles of Path element

In WPF or Silverlight application, the vectorial is king. It is for this reason that as soon as I can, I use a Path instead of a picture.

Therefore, you can have the same Path several times in the application. The temptation is strong to create a Style with a value in the Data property.

Unfortunately, there is a known bug with this property. When it is used in a style, the path is instantiated once. That is to say that if you have for example a list of item that uses the same style, only the first will be displayed. No error, but not the expected behavior.

There are various methods to get round this problem, defining a PathGeometry in the style or creating a control that contains a Path.

Solution with a PathGeometry:

<Style x:Key="DownCaret" TargetType="Path">
    <Setter Property="Stretch" Value="Fill" />
    <Setter Property="Height" Value="6" />
    <Setter Property="Width" Value="10" />
    <Setter Property="HorizontalAlignment" Value="Center" />
    <Setter Property="VerticalAlignment" Value="Center" />
    <Setter Property="Fill" Value="#FF333333" />
    <Setter Property="Data">
            <PathGeometry FillRule="EvenOdd">
                <PathFigure IsClosed="True" StartPoint="0,0">
                    <LineSegment Point="2.25,0" />
                    <LineSegment Point="4,2" />
                    <LineSegment Point="5.75,0" />
                    <LineSegment Point="8,0" />
                    <LineSegment Point="4,4.75" />
    <!--<Setter Property="Data" Value="M0,0 L2.25,0 L4,2 L5.75,0 L8,0 L4,4.75 z" />-->

You can learn more with this topic on the Microsoft forum: http://forums.silverlight.net/p/220489/527412.aspx

Tags: WPF, Silverlight, XAML

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