Ext.data.ChinaStore = Ext.extend(Ext.data.Store, {
    sortData : function(f, direction){
        direction = direction || 'ASC';
        var st = this.fields.get(f).sortType;
        var fn = function(r1, r2){
            var v1 = st(r1.data[f]), v2 = st(r2.data[f]);
            return v1.localeCompare(v2);
            //
        };
        this.data.sort(direction, fn);
        if(this.snapshot && this.snapshot != this.data){
            this.snapshot.sort(direction, fn);
        }
    }
});