检索元素与WHERE条件使用XML LINQ同名

Question

我的XML是像下面

<Exchange> 
    <Rec> 
     <data headers="Currency">USD</data> 
     <data headers="Value">1.0609</data> 
    </Rec> 
    <Rec> 
     <data headers="Currency">GBP</data> 
     <data headers="Value">0.6694</data> 
    </Rec> 
    <Rec> 
     <data headers="Currency">INR</data> 
     <data headers="Value">54.123</data> 
    </Rec> 
</Exchange> 

我要检索值（1.0609）使用XML的LINQ 取决于货币（美元）在asp.net

Answer 1

这是一种方法。虽然不是特别优雅。

var doc = XDocument.Load(@"<path>\exchange.xml"); 

// convert xml to List<> containing Currency and Value 
var q = doc.Element("Exchange").Elements("Rec").Select (e => 
    new { 
     Currency = e.Elements("data"). 
       Where (x => "Currency" == (string) x.Attribute("headers")). 
       Select (x => (string)x).Single(), 

     Value = e.Elements("data"). 
       Where (x => "Value" == (string) x.Attribute("headers")). 
       Select (x => (double)x).Single(), 
    } 
); 

// select the value we're after 
var q1 = q.Where (x => x.Currency == "USD").Select (x => x.Value).Single(); 

q1.Dump(); 

Answer 2

var xml = XElement.Load("XMLFile1.xml"); 

string curr = "USD"; 
var number = (from node in xml.Elements("Rec").Elements("data") 
    where (string)node.Attribute("headers") == "Currency" && node.Value == curr 
    select node into data 
    from value in data.Parent.Elements("data") 
    where (string)value.Attribute("headers") == "Value" 
    select (double)value).FirstOrDefault();