[英]c# LINQ-to-XML update (save) list of elements in file after ordering
我有一個XML文件:
<?xml version="1.0" encoding="utf-8"?>
<FooMgr>
<BlargDate>2017-03-06 10:26:21</BlargDate>
<Bars>
<Bar>
<BarId>222</BarId>
<BarVal>QWERTY</BarVal>
</Bar>
<Bar>
<BarId>77</BarId>
<BarVal>DVORAK</BarVal>
</Bar>
<Bar>
<BarId>9999</BarId>
<BarVal>AZERTY</BarVal>
</Bar>
</Bars>
</FooMgr>
我是:
雖然添加的元素在我保存之后位於列表中,但它在保存時不保留我在代碼中定義的順序。 這是我到目前為止(主要是工作有效代碼)
//read in the xml file
XDocument doc = XDocument.Load(...);
//add a new 'Bar' element
XElement bar1 = new XElement("Bar",
new XElement("BarId", 101),
new XElement("BarVal", "HCESAR"));
doc.Element("FooMgr").Element("Bars").Add(bar1);
//sort descending by BarId
IEnumerable<XElement> allBars = doc.Descendants("FooMgr")
.Select(x => x.Element("Bars"))
.Descendants("Bar")
.ToArray();
allBars = allBars.OrderByDescending(s => int.Parse(s.Element("BarId").Value));
//save file
doc.Save(...);
// note: at this point the file successfully saves (along with the
// new 'bar' value, but the order that is set for allBars does not
// make it back into the file.
雖然這行:
allBars = allBars.OrderByDescending(s => int.Parse(s.Element("BarId").Value));
似乎正確地對代碼中的'Bars'元素進行排序,當我將其保存回文件時,訂單不會保留。
有什么想法嗎?
首先,你的xml無效,我猜對了:
<?xml version="1.0" encoding="utf-8"?>
<FooMgr>
<BlargDate>2017-03-06 10:26:21</BlargDate>
<Bars>
<Bar>
<BarId>222</BarId>
<BarVal>QWERTY</BarVal>
</Bar>
<Bar>
<BarId>77</BarId>
<BarVal>DVORAK</BarVal>
</Bar>
<Bar>
<BarId>9999</BarId>
<BarVal>AZERTY</BarVal>
</Bar>
</Bars>
</FooMgr>
你的allBars只是一個節點的集合,它不屬於任何節點,所以你需要將它掛在Bars下,我建議先刪除那里的所有項目:
XElement bar1 = new XElement("Bar",
new XElement("BarId", 101),
new XElement("BarVal", "HCESAR"));
doc.Element("FooMgr").Element("Bars").Add(bar1);
//sort descending by BarId
IEnumerable<XElement> allBars = doc.Descendants("FooMgr")
.Select(x => x.Element("Bars"))
.Descendants("Bar")
.ToArray();
allBars = allBars.OrderByDescending(s => int.Parse(s.Element("BarId").Value));
doc.Element("FooMgr").Element("Bars").RemoveAll();
doc.Element("FooMgr").Element("Bars").Add(allBars);
在VB中這將是
Dim doc As XElement
' to load from a file
'xe = XElement.Load(yourpath)
' for testing
doc = <FooMgr>
<BlargDate>2017-03-06 10:26:21</BlargDate>
<Bars>
<Bar>
<BarId>222</BarId>
<BarVal>QWERTY</BarVal>
</Bar>
<Bar>
<BarId>77</BarId>
<BarVal>DVORAK</BarVal>
</Bar>
<Bar>
<BarId>9999</BarId>
<BarVal>AZERTY</BarVal>
</Bar>
</Bars>
</FooMgr>
doc.<Bars>.LastOrDefault.Add(<Bar>
<BarId>101</BarId>
<BarVal>HCESAR</BarVal>
</Bar>)
Dim ie As List(Of XElement) = doc.<Bars>.Elements.OrderBy(Function(el) Integer.Parse(el.<BarId>.Value)).ToList
doc.<Bars>.Elements.Remove()
doc.<Bars>.FirstOrDefault.Add(ie)
' to save file
' doc.Save(yourpath)
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