Создайте сетку HorizontalAlignment
Stretch
, а не Left
.
<DataTemplate x:Key="DataTemplate" DataType="{x:Type c:Place}">
<Grid HorizontalAlignment="Stretch">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="40"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" Text="{Binding Name}"/>
<TextBlock Grid.Column="1" Text="{Binding State}" TextAlignment="Right"/>
</Grid>
</DataTemplate>