操作 DataProvider

使用 addItem() 和 addItemAt() 方法可以将项目添加到 DataProvider 中。下面的示例添加用户在可编辑的 ComboBox 的文本字段中输入的项目。在此示例中，假定已将一个 ComboBox 拖到舞台上并已为其指定实例名称 aCb。

import fl.data.DataProvider;
import fl.events.ComponentEvent;

var items:Array = [
{label:"Roger"},
{label:"Carolyn"},
{label:"Darrell"},
{label:"Rebecca"},
{label:"Natalie"},
{label:"Mitchell"},
];
aCb.dataProvider = new DataProvider(items);
 
aCb.addEventListener(ComponentEvent.ENTER, newItemHandler);
  
function newItemHandler(event:ComponentEvent):void {
    var newRow:int = event.target.length + 1;
     event.target.addItemAt({label:event.target.selectedLabel},
        event.target.length);
}

还可以通过组件的 DataProvider 替换和删除组件中的项目。下面的示例实现了两个单独的 List 组件 listA 和 listB，并提供了一个标签为"Sync"的 Button。用户单击此 Button 时，此示例将使用 replaceItemAt() 方法用 listA 中的项目替换 listB 中的项目。如果 listA 比 listB 长，此示例将调用 addItem() 方法向 listB 添加额外的项目。如果 listB 比 listA 长，此示例将调用 removeItemAt() 方法删除 listB 中多余的项目。

// Requires the List and Button components to be in the library

import fl.controls.List;
import fl.controls.Button;
import flash.events.Event;
import fl.data.DataProvider;

var listA:List = new List();
var listB:List = new List();
var syncButton:Button = new Button();
syncButton.label = "Sync";

var itemsA:Array = [
{label:"David"},
{label:"Colleen"},
{label:"Sharon"},
{label:"Ronnie"},
{label:"James"},
];
var itemsB:Array = [
{label:"Roger"},
{label:"Carolyn"},
{label:"Darrell"},
{label:"Rebecca"},
{label:"Natalie"},
{label:"Mitchell"},
];
listA.dataProvider = new DataProvider(itemsA);
listB.dataProvider = new DataProvider(itemsB);

addChild(listA);
addChild(listB);
addChild(syncButton);

listA.move(100, 100);
listB.move(250, 100);
syncButton.move(175, 220);

syncButton.addEventListener(MouseEvent.CLICK, syncHandler);

function syncHandler(event:MouseEvent):void {
    var i:uint = 0;
    if(listA.length > listB.length) {     //if listA is longer, add items to B
        while(i < listB.length) {
            listB.dataProvider.replaceItemAt(listA.dataProvider.getItemAt(i), i);
            ++i;
        }
        while(i < listA.length) {
            listB.dataProvider.addItem(listA.dataProvider.getItemAt(i++));
        }
    } else if(listA.length == listB.length) { //if listA and listB are equal length
        while(i < listB.length) {
            listB.dataProvider.replaceItemAt(listA.dataProvider.getItemAt(i), i);
            ++i;
        }
    } else {                //if listB is longer, remove extra items from B
        while(i < listA.length) {
            listB.dataProvider.replaceItemAt(listA.dataProvider.getItemAt(i), i);
            ++i;
        }
        while(i < listB.length) {
            listB.dataProvider.removeItemAt(i++);
        }
    }
}

还可以使用 merge()、sort() 和 sortOn() 方法合并 DataProvider 以及对其进行排序。下面的示例用两个垒球队的部分花名册填充两个 DataGrid 实例（aDg 和 bDg）。它添加一个标签为 Merge 的 Button，当用户单击此 Button 时，事件处理函数 (mrgHandler) 将合并 bDg 和 aDg 的花名册，并按最终 DataGrid 的"Name"列对其进行排序。

import fl.data.DataProvider;
import fl.controls.DataGrid;
import fl.controls.Button;

var aDg:DataGrid = new DataGrid();
var bDg:DataGrid = new DataGrid();
var mrgButton:Button = new Button();
addChild(aDg);
addChild(bDg);
addChild(mrgButton);
bldRosterGrid(aDg);
bldRosterGrid(bDg);
var aRoster:Array = new Array();
var bRoster:Array = new Array();
aRoster = [
        {Name:"Wilma Carter", Bats:"R", Throws:"R", Year:"So", Home: "Redlands, CA"}, 
        {Name:"Sue Pennypacker", Bats:"L", Throws:"R", Year:"Fr", Home: "Athens, GA"},
        {Name:"Jill Smithfield", Bats:"R", Throws:"L", Year:"Sr", Home: "Spokane, WA"},
        {Name:"Shirley Goth", Bats:"R", Throws:"R", Year:"Sr", Home: "Carson, NV"}
];
bRoster = [
        {Name:"Angelina Davis", Bats:"R", Throws:"R", Year:"So", Home: "Odessa, TX"},
        {Name:"Maria Santiago", Bats:"L", Throws:"L", Year:"Sr", Home: "Tacoma, WA"},
        {Name:"Debbie Ferguson", Bats:"R", Throws:"R", Year: "Jr", Home: "Bend, OR"}
];
aDg.dataProvider = new DataProvider(aRoster);
bDg.dataProvider = new DataProvider(bRoster);
aDg.move(50,50);
aDg.rowCount = aDg.length;
bDg.move(50,200);
bDg.rowCount = bDg.length;
mrgButton.label = "Merge";
mrgButton.move(200, 315);
mrgButton.addEventListener(MouseEvent.CLICK, mrgHandler);

function bldRosterGrid(dg:DataGrid){
    dg.setSize(400, 300);
    dg.columns = ["Name", "Bats", "Throws", "Year", "Home"];
    dg.columns[0].width = 120;
    dg.columns[1].width = 50;
    dg.columns[2].width = 50;
    dg.columns[3].width = 40;
    dg.columns[4].width = 120;
};

function mrgHandler(event:MouseEvent):void {
    aDg.dataProvider.merge(bDg.dataProvider);
    aDg.dataProvider.sortOn("Name");
}