アプリ実行
![f:id:JHashimoto:20131014182335p:image f:id:JHashimoto:20131014182335p:image](http://cdn-ak.f.st-hatena.com/images/fotolife/J/JHashimoto/20131014/20131014182335.png)
4つ全て指定すると、TopとLeftが優先されるようですね。
ソースコード
App.xaml
<Application xClass="HelloWorld.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlnsx="http://schemas.microsoft.com/winfx/2006/xaml"
StartupUri="MainWindow.xaml">
</Application>
MainWindow.xaml
<Window xClass="WpfApplication4.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlnsx="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Canvas Width="200" Height="100" Background="Aqua">
<TextBlock CanvasRight="2" CanvasTop="2">Top, Right</TextBlock>
<TextBlock CanvasLeft="2" CanvasTop="2">Top, Left</TextBlock>
<TextBlock CanvasRight="2" CanvasBottom="2">Bottom, Right</TextBlock>
<TextBlock CanvasLeft="2" CanvasBottom="2">Bottom, Left</TextBlock>
<TextBlock CanvasLeft="20" CanvasBottom="20" CanvasRight="20" CanvasTop="20">4つすべて</TextBlock>
</Canvas>
</Window>