Defines the columns of a grid.

Each child of a columns element should be a org.zkoss.zul.Column element.

<window title="Grid Demo" border="normal" width="360px">
    <zscript>    
    class Comp implements Comparator {    
        private boolean _asc;        
        public Comp(boolean asc) {        
            _asc = asc;            
        }        
        public int compare(Object o1, Object o2) {        
            String s1 = o1.getChildren().get(0).getValue(),            
                s2 = o2.getChildren().get(0).getValue();                
            int v = s1.compareTo(s2);            
            return _asc ? v: -v;            
        }        
    }    
    Comp asc = new Comp(true), dsc = new Comp(false);    
    </zscript>    
    <grid>    
        <columns sizable="true">        
            <column label="Type" sortAscending="&#36;{asc}" sortDescending="&#36;{dsc}"/>            
            <column label="Content"/>            
        </columns>        
        <rows>        
            <row>            
                <label value="File:"/>                
                <textbox width="99%"/>                
            </row>            
            <row>            
                <label value="Type:"/>                
                <hbox>                
                    <listbox rows="1" mold="select">                    
                        <listitem label="Java Files,(*.java)"/>                        
                        <listitem label="All Files,(*.*)"/>                        
                    </listbox>                    
                    <button label="Browse..."/>                    
                </hbox>                
            </row>            
            <row>            
                <label value="Options:"/>                
                <textbox rows="3" width="99%"/>                
            </row>            
        </rows>        
    </grid>    
</window>