Here’s a little time saver. I sort of have a routine that I go through when I create a new WPF project. One of those things is to create a resource dictionary (I’m down to one on most projects now, but more on that later) that includes some common stuff that is nice to be able to depend on while your cranking out XAML.

Among those, are these super simple geometry resources:

<Geometry x:Key="DownArrow">M0,0 L1,0 0.5,1Z</Geometry>
<Geometry x:Key="UpArrow">M0,1 L1,1 0.5,0Z</Geometry>
<Geometry x:Key="RightArrow">M0,0 L1,0.5 0,1Z</Geometry>
<Geometry x:Key="LeftArrow">M0,0.5 L1,1 1,0Z</Geometry>
<Geometry x:Key="CloseX">M0,0 L1,1 M0,1 L1,0</Geometry>

Simple, but handy when you (inevitably) need to bust out an arrow for some reason. You use them like this:

<!-- DownArrow -->
<Path Data="{StaticResource DownArrow}" Width="10" Height="8"
  Stretch="Fill" Fill="Black" />

<!-- CloseX -->
<Path Data="{StaticResource CloseX}" Width="12" Height="12"
  Stretch="Fill" Stroke="Black" StrokeThickness="3" Margin="10" />

All together, they look like this: 

The geometries themselves all happen within a real coordinate space of a pixel, so it’s important to set the Stretch property to Fill, that way the geometry with stretch to the size of the Path element.

Unfortunately, this is WPF only. Silverlight (SL2 at least) doesn’t like to work with Geometries as resources. If someone tries it out in SL3, let me know how it goes.

Update: Dr. WPF (ironically) suggested a sweet workaround for Silverlight. Instead of adding the resources as Geometries, add them as strings, like this:

<Grid
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:sys="clr-namespace:System;assembly=mscorlib">
  <Grid.Resources>
    <sys:String x:Key="DownArrow">M0,0 L1,0 0.5,1Z</sys:String>
    <sys:String x:Key="UpArrow">M0,1 L1,1 0.5,0Z</sys:String>
    <sys:String x:Key="RightArrow">M0,0 L1,0.5 0,1Z</sys:String>
    <sys:String x:Key="LeftArrow">M0,0.5 L1,1 1,0Z</sys:String>
    <sys:String x:Key="CloseX">M0,0 L1,1 M0,1 L1,0</sys:String>
  </Grid.Resources>
</Grid>

The usage from XAML is then exactly the same as WPF. Nice one, doc!

from:http://nerdplusart.com/simple-path-data-resources-that-i-add-to-every-wpf-project/

Simple Path Data Resources that I Add to Every WPF and Silverlight Project