# aardio 范例: sqlite 库 - 虚表



```aardio
//sqlite 库 - 虚表
//相关范例：范例 » Windows 窗口 » 列表视图控件 » 虚表
//下面listview 控件的类名（cls属性）请改为 "vlistview"
import win.ui;
/*DSG{{*/
winform = win.form(text="虚表";right=805;bottom=610)
winform.add(
listview={cls="vlistview";left=27;top=17;right=778;bottom=564;anchors={left=1;top=1;right=1;bottom=1};edge=1;z=1}
)
/*}}*/

winform.listview.insertColumn("网址", 200);
winform.listview.insertColumn("评论", 200);

//创建测试数据
import sqlite; 
var db = sqlite(":memory:")
if (!db.existsTable("homepage2")) {
	db.exec("CREATE TABLE homepage2 (url char(30), comment char(20))");
	
	db.beginTrans()
	for (i = 1; 100) {
		db.exec("INSERT INTO homepage2(url, comment) VALUES(@url,@comment)", {
			url = "https://www.aardio.com";
			comment = "字符串包含'单引号' " ++ i;
		});
	}
	db.commitTrans()
}

//指定虚表行数
winform.listview.count = db.stepResult("SELECT count(*) FROM homepage2")[1];

//数据库缓存表
var cacheTable = table.cache(
	lambda(row) db.stepResult("SELECT * FROM homepage2 Limit 1 Offset %d",row-1) 
);

//获取虚表项
winform.listview.onGetDispItem = lambda(item,row,col){text=cacheTable[row][col]}; 

winform.listview.onDestroy = function(){
	db.close();
}

winform.show();
win.loopMessage();
```