如何在Apache Royale上设置basic js|DataGrid上的列100%宽度

import org.apache.royale.core.IItemRenderer;
import org.apache.royale.core.ItemRendererClassFactory;
import org.apache.royale.events.Event;
import org.apache.royale.html.DataGrid;
import org.apache.royale.html.beads.models.ArrayCollection;
import org.apache.royale.utils.loadCSS;

public class Main extends Sprite {
    public function Main() {
        loadCSS("styles.css");

        var data:ArrayCollection = new ArrayCollection([
            {name: "John", age: 30},
            {name: "Jane", age: 25}
        ]);

        var dataGrid:DataGrid = new DataGrid();
        dataGrid.dataProvider = data;

        // 设置第一列宽度为 100%
        var columns:Array = dataGrid.columns;
        columns[0].width = "100%";

        addChild(dataGrid);

        dataGrid.addEventListener(Event.COMPLETE, function():void {
            trace("DataGrid loaded");
        });
    }
}