How to make TextBox stretch horizontally to fill width of ListBox?

In the following XAML, the first two TextBoxes fill the horizontal width of the StackPanel by default.  But regardless of whether I add HorizontalAlignment="Stretch" or HorizontalContentAlignment="Stretch" attributes to the following ListBoxes, their TextBoxes will not fill the full width of the ListBox.

How can I get that effect without using fixed widths?

<StackPanel>
    <TextBox Text="abc1" />

    <Grid>
        <TextBox Text="abc2" />
    </Grid>

    <ListBox>
        <TextBox Text="abc3" />
    </ListBox>

    <ListBox>
        <Grid>
            ...