Linq to xml 這個(gè)東西出來好多年了,但一直沒有機(jī)會(huì)在項(xiàng)目中用到,前段時(shí)間,終于項(xiàng)目中一些地方需要用到xml作為數(shù)據(jù)源,于是就體驗(yàn)了一把這個(gè),感覺還挺不錯(cuò)的,今天在此小結(jié)一下.
首先我們來模擬一下一個(gè)真實(shí)的業(yè)務(wù)場景:在這里我們需要展示一個(gè)火車站上各個(gè)站臺上面燈光開關(guān)狀態(tài).假設(shè)每個(gè)站臺一共6個(gè)開關(guān),站臺我們用Station節(jié)點(diǎn)表示,站臺開關(guān)我們用SwitchNo來表示,在初始化(即默認(rèn)狀態(tài))的時(shí)候,我們需要表示成第一個(gè)站臺2個(gè)開關(guān)開著,第二個(gè)站臺3個(gè)開關(guān)開著,第三個(gè)站臺4個(gè)開關(guān)開著….
那么我們可能需要的一個(gè)xml文件格式可能就是如下這個(gè)樣子:
<?xml version="1.0" encoding="utf-8"?>
<Stations>
<Station Id="1">
<SwitchNo Id="1">1</SwitchNo>
<SwitchNo Id="2">1</SwitchNo>
<SwitchNo Id="3">0</SwitchNo>
<SwitchNo Id="4">0</SwitchNo>
<SwitchNo Id="5">0</SwitchNo>
<SwitchNo Id="6">0</SwitchNo>
</Station>
<Station Id="2">
<SwitchNo Id="1">1</SwitchNo>
<SwitchNo Id="2">1</SwitchNo>
<SwitchNo Id="3">1</SwitchNo>
<SwitchNo Id="4">0</SwitchNo>
<SwitchNo Id="5">0</SwitchNo>
<SwitchNo Id="6">0</SwitchNo>
</Station>
<Station Id="3">
<SwitchNo Id="1">1</SwitchNo>
<SwitchNo Id="2">1</SwitchNo>
<SwitchNo Id="3">1</SwitchNo>
<SwitchNo Id="4">0</SwitchNo>
<SwitchNo Id="5">0</SwitchNo>
<SwitchNo Id="6">0</SwitchNo>
</Station>
<Station Id="4">
<SwitchNo Id="1">0</SwitchNo>
<SwitchNo Id="2">0</SwitchNo>
<SwitchNo Id="3">1</SwitchNo>
<SwitchNo Id="4">1</SwitchNo>
<SwitchNo Id="5">0</SwitchNo>
<SwitchNo Id="6">0</SwitchNo>
</Station>
<Station Id="5">
<SwitchNo Id="1">1</SwitchNo>
<SwitchNo Id="2">1</SwitchNo>
<SwitchNo Id="3">1</SwitchNo>
<SwitchNo Id="4">1</SwitchNo>
<SwitchNo Id="5">1</SwitchNo>
<SwitchNo Id="6">0</SwitchNo>
</Station>
<Station Id="6">
<SwitchNo Id="1">1</SwitchNo>
<SwitchNo Id="2">1</SwitchNo>
<SwitchNo Id="3">1</SwitchNo>
<SwitchNo Id="4">1</SwitchNo>
<SwitchNo Id="5">1</SwitchNo>
<SwitchNo Id="6">1</SwitchNo>
</Station>
</Stations>
下面我們就從xml數(shù)據(jù)的創(chuàng)建/查詢/修改這三個(gè)方面簡單談一下吧.關(guān)于概念啥的就不啰嗦了,直接上代買吧.
1. 創(chuàng)建這個(gè)文件
/// <summary>
/// 創(chuàng)建xml文件
/// </summary>
private void writeStationXmlData()
{
string fileName = Path.Combine(dataPath, "StationWitch.xml");
if (!Directory.Exists(dataPath))
Directory.CreateDirectory(dataPath);
if (File.Exists(fileName))
return;
var stationEleList = new List<XElement>(); //臨時(shí)緩存每個(gè)站臺節(jié)點(diǎn)
//一共6個(gè)站臺,循環(huán)創(chuàng)建
for (int i = 1; i < 7; i++)
{
var xAttr = new XAttribute("Id", i);
//臨時(shí)緩存每個(gè)每個(gè)站臺下的開關(guān)狀態(tài)
var childList = new List<XElement>();
for (int j = 1; j < 7; j++)
{
childList.Add(new XElement("SwitchNo", new XAttribute("Id", j), i >= j ? 1 : 0));
}
//構(gòu)建一個(gè)站臺節(jié)點(diǎn)
var stationEle = new XElement("Station", xAttr, childList.ToArray());
stationEleList.Add(stationEle);
}
//構(gòu)建Stations節(jié)點(diǎn)
XElement xBody = new XElement("Stations", stationEleList.ToArray());
//構(gòu)建整個(gè)文檔
XDocument doc = new XDocument(
new XDeclaration("1.0", "utf-8", "yes"), xBody);
doc.Save(fileName);
}
2. 讀取當(dāng)前xml 文件并轉(zhuǎn)化為友好的類型
/// <summary>
/// 查詢讀取每個(gè)站臺的開關(guān)狀態(tài)并轉(zhuǎn)化為keyValue鍵值對
/// </summary>
/// <returns></returns>
public IList<KeyValue<int, int>> GetStationLightData()
{
writeStationXmlData();
if (stationLightData == null)
{
stationLightData = new List<KeyValue<int, int>>();
stationSwitchStatus = new List<KeyValue<int, bool>>();
//加載xml
string fileName = Path.Combine(dataPath, "StationWitch.xml");
XElement doc = XElement.Load(fileName);
//讀取站臺列表
var station = from s in doc.Descendants("Station")
select s;
//遍歷站臺
foreach (var st in station)
{
//獲取每個(gè)站臺的開關(guān)集合 即SwitchNo節(jié)點(diǎn)
var st_switchs = st.Elements("SwitchNo");
var stationId = int.Parse(st.Attribute("Id").Value);
int light = 0;
foreach (var sw in st_switchs)
{
var swithNo = int.Parse(sw.Attribute("Id").Value);
bool isOn = sw.Value == "1";
if (isOn)
light += 20;
stationSwitchStatus.Add(new KeyValue<int, bool>(stationId, isOn, swithNo));
}
stationLightData.Add(new KeyValue<int, int>(stationId, light));
}
}
return stationLightData;
}
3.更新節(jié)點(diǎn)值(先查詢找到指定的節(jié)點(diǎn) 在更新后保存)
/// <summary>
/// 更新制定站臺中的指定開關(guān)的狀態(tài),即更新制定Station->SwitchNo節(jié)點(diǎn)下值
/// </summary>
/// <param name="station"></param>
/// <param name="switchNo"></param>
/// <param name="isOn"></param>
public void UpdateStationSwitchStatus(int station, int switchNo, bool isOn)
{
string fileName = Path.Combine(dataPath, "StationWitch.xml");
//讀取數(shù)據(jù)
XElement doc = XElement.Load(fileName);
var up_station = doc.Descendants("Station")
.Where(o => o.Attribute("Id").Value == station.ToString()).FirstOrDefault();
//找出指定的節(jié)點(diǎn)
var upSwitch = up_station.Elements("SwitchNo").FirstOrDefault(o => o.Attribute("Id").Value == switchNo.ToString());
//更新
if (upSwitch != null)
{
upSwitch.Value = isOn ? "1" : "0";
}
//保存為文件
lock (sync)
{
doc.Save(fileName);
}
}
至此,xml的常規(guī)操作就介紹完了,希望能對有需要的同學(xué)有所幫助.