WPF GridViewColumn Width 100 percent

<local:ListViewEx.View>

    <GridView ColumnHeaderContainerStyle="{StaticResource CustomHeaderStyle}">

        <GridViewColumn Header="xxx" 
             Width="{Binding RelativeSource={RelativeSource FindAncestor, 
             AncestorType=ListView}, Path=ActualWidth}">

             <GridViewColumn.CellTemplate>