How to set width to 100% in WPF - wpf

Question

Is there any way how to tell component in WPF to take 100% of available space?
Like
width: 100%;
in CSS
I've got this XAML, and I don't know how to force Grid to take 100% width.
<ListBox Name="lstConnections">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Background="LightPink">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Text="{Binding Path=User}" Margin="4"></TextBlock>
<TextBlock Grid.Row="0" Grid.Column="1" Text="{Binding Path=Password}" Margin="4"></TextBlock>
<TextBlock Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2" Text="{Binding Path=Host}" Margin="4"></TextBlock>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Result looks like
alt text http://foto.darth.cz/pictures/wpf_width.jpg
I made it pink so it's obvious how much space does it take. I need to make the pink grid 100% width.

Answer 1

It is the container of the Grid that is imposing on its width. In this case, that's a ListBoxItem, which is left-aligned by default. You can set it to stretch as follows:
<ListBox>
<!-- other XAML omitted, you just need to add the following bit -->
<ListBox.ItemContainerStyle>
<Style TargetType="ListBoxItem">
<Setter Property="HorizontalAlignment" Value="Stretch"/>
</Style>
</ListBox.ItemContainerStyle>
</ListBox>

Answer 2

You could use HorizontalContentAlignment="Stretch" as follows:
<ListBox HorizontalContentAlignment="Stretch"/>