如何获取XML节点值

Question

I have an xml that looks like this:

<ProductTemplate ProductName="FlamingoWhistle" Version="1.8.02" >
    <Whistle Type="Red" Version="3.0.5" />
        <Size Type="Large" Version="1.0" />
    <Whistle Type="Blue" Version="2.4.3" />
</ProductTemplate>  

How can I check if type equals red, return the version for that type?
This is what I have tried but fails if the element isn't first

XElement root = XElement.Load(path);

if (XPathSelectElement("Whistle").Attribute("Type") == "Blue")
{
    Console.WriteLine(XPathSelectElement("Whistle").Attribute("Version").value));
}
else
{
    Console.WriteLine("Sorry, no FlamingoWhistle in that color");
}

Answer 1

this should do the trick

foreach(XElement xe in root.Elements("Whistle"))
{
    if (xe.Attribute("Type").Value == "Red")
    {
        Console.WriteLine(xe.Attribute("Version").Value);
    }
}

use linq

string version = root.Elements("Whistle")
                 .Where(x => x.Attribute("Type").Value == "Red")
                 .First().Attribute("Version").Value;

xpath

string version = root.XPathSelectElement("Whistle[@Type='Red']").Attribute("Version").Value;

update

first of all you may need to correct the xml for property hierarchy, in your current xml element Size is not a child of Whistle. i assume it to be the child

<ProductTemplate ProductName="FlamingoWhistle" Version="1.8.02">
    <Whistle Type="Red" Version="3.0.5">
        <Size Type="Large" Version="1.0" /> 
    </Whistle>
    <Whistle Type="Blue" Version="2.4.3" /> 
</ProductTemplate>

retrieving the version from size element

foreach (XElement xe in root.Elements("Whistle"))
{
    if (xe.Attribute("Type").Value == "Red")
    {
        Console.WriteLine(xe.Element("Size").Attribute("Version").Value);
    }
}

linq

string version = root.Elements("Whistle")
     .Where(x => x.Attribute("Type").Value == "Red")
     .First().Element("Size").Attribute("Version").Value;

xpath

string version = root.XPathSelectElement("Whistle[@Type='Red']/Size").Attribute("Version").Value;