I assume that when you say βresizeβ, you mean that you want to stretch the elements in both directions. To use the default ListBox and stretch the elements horizontally, you need to:
<ListBox HorizontalContentAlignment="Stretch"/>
The default value is Left, so all ListBoxItems are inserted to the left and are individually sized depending on their contents.
StackPanel, , . - UniformGrid, - , , . VerticalContentAlignment ( Center). , , :
<ListBox HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<UniformGrid Columns="1"/>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
</ListBox>