[英]Optimisation of LinqToXml
谁能告诉我这是否正确,或者是否有更快/更清洁的方法来做到这一点?
//I load p as a xDoc so I can use linq to xml
XDocument myDoc = XDocument.Parse(p);
// retrieve each "Item" node except if orderedQuantity is 0 or name is "nullorderitem"
IEnumerable<XElement> orderedRes = from item in myDoc.Descendants("Item")
where ((double)item.Element("orderedQuantity") > 0 && item.Element("ResourceId").Name != "NULLOrderItem")
select item;
foreach (XElement xelem in orderedRes)
{
if(xelem.Element("Name").Value.ToLower() == "oneofmyvalueIneed"
|| xelem.Element("Name").Value.ToLower() == "anotherone"
|| xelem.Element("Name").Value.ToLower() == "yetanother")
{
FieldProperties elem = new FieldProperties();
elem.Fieldname = xelem.Element("Name").Value;
elem.Fieldvalue = xelem.Element("OrderedQuantity").Value;
lElem.Add(elem);
}
}
知道 lElem 是一个 FieldProperties 列表,而 FieldProperties 是一个看起来像这样的类:
FieldProperties
string fieldname
string fieldvalue
和 p 是一个字符串,看起来像
<items>
<item>
<resourceid>blablabla</resourceid>
<somerandomtag>whocares</somerandomtag>
<orderedquantity>0.0</orderedquantity>
</item>
<item>
<resourceid>oneofmyvalueIneed</resourceid>
<somerandomtag>whocares</somerandomtag>
<orderedquantity>1.0</orderedquantity>
</item>
<item>
<resourceid>yetanother</resourceid>
<somerandomtag>whocares</somerandomtag>
<orderedquantity>0.0</orderedquantity>
</item>
</items>
您可以使用.Contains
方法改进if
语句。
var validNames = new List<string> {"oneofmyvalueIneed","anotherone","yetanother"}
XDocument myDoc = XDocument.Parse(p);
var result = from item in myDoc.Descendants("Item")
where ((double)item.Element("orderedQuantity") > 0 &&
item.Element("ResourceId").Name != "NULLOrderItem") && // See Charles's comment about this line
validNames.Contains(iten.Element("Name").Value.ToLower())
select item;
foreach (var item in orderedRes)
{
FieldProperties elem = new FieldProperties();
elem.Fieldname = xelem.Element("Name").Value;
elem.Fieldvalue = xelem.Element("OrderedQuantity").Value;
lElem.Add(elem);
}
然后你也可以用foreach
替换
select new FieldProperties
{
Fieldname = item.Element("Name").Value,
Fieldvalue = xelem.Element("OrderedQuantity").Value
};
在访问子元素时将它们全部添加在一起+一些优化,它看起来像:
var validNames = new List<string> {"oneofmyvalueIneed","anotherone","yetanother"}
XDocument myDoc = XDocument.Parse(p);
var result = from item in myDoc.Descendants("Item")
let value = item.Element("orderedQuantity")
let name = iten.Element("Name").Value.ToLower()
where ((double)value > 0 &&
item.Element("ResourceId").Name != "NULLOrderItem") && // See Charles's comment about this line
validNames.Contains(name)
select new FieldProperties
{
Fieldname = name
Fieldvalue = value
};
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