找不到商品名称C＃XML

Question

I'm having a problem with my XML document.

I want my program to find all values of the items in my XML file, but only if the handlingType is of a certain character bunch.

Code (C#) :

string path = "//files//handling.meta";

             var doc = XDocument.Load(path);

            var items = doc.Descendants("HandlingData").Elements("Item");

            var query = from i in items

                        select new
                         {
                             HandlingName = (string)i.Element("handlingName"),
                             HandlingType = (string)i.Element("HandlingType"),
                             Mass = (decimal?)i.Element("fMass")
                         };
            foreach (var HandlingType in items)
            {
                if (HandlingType.ToString() == "HANDLING_TYPE_FLYING")
                {
                    MessageBox.Show(HandlingType.ToString());
                }
            }

The above code demonstraights a short version of what I want to happen, but fails to find this handlingType (does not show the messageBox)

Here's the XML :

<CHandlingDataMgr>
    <HandlingData>
        <Item type="CHandlingData">
            <handlingName>Plane</handlingName>
            <fMass value="380000.000000"/>
            <handlingType>HANDLING_TYPE_FLYING</handlingType>
        </Item>
        <Item type="CHandlingData">
            <handlingName>Car1</handlingName>
            <fMass value="150000.000000"/>
            <handlingType>HANDLING_TYPE_DRIVING</handlingType>
        </Item>
    </HandlingData>
</CHandlingDataMgr>

I would like the output to show the handlingName if it contains a certain HandlingType For eg

if (handlingType == "HANDLING_TYPE_FLYING") 
{
    messageBox.Show(this.HandlingName);
}

My problem in short : Program does not find item's handling type, it does find the tag but when asked to display, returns empty/shows as nothing.

Edit: Also in the XML handling_type_flying contains extra elements such as thrust that cannot be found in each item (such as car), I would like the program to also find these elements. (this is a second problem I'm facing, maybe should ask 2nd ques?)

Answer 1

Several things that need fixing.

1. you are not using your query in your foreach loop. foreach (var item in query)
2. Your element has an upercase "H" but should be lowercase "handlingType". HandlingType = (string)i.Element("handlingType"),
3. You are not pulling the Attribute value of your fMass element. Mass = i.Element("fMass").Attribute("value").Value
4. Once you adjust your Query in your foreach loop you then need to adjust the loop to account for looping over your newly made object.
5. NOTE that I removed (decimal) from Mass = i.Element("fMass").Attribute("value").Value

here is the code with all the fixes.

  class Program
    {
        static void Main()
        {
            const string path = "//files//handling.meta";
            var doc = XDocument.Load(path);

            var items = doc.Descendants("HandlingData").Elements("Item");

            var query = from i in items

                        select new
                        {
                            HandlingName = (string)i.Element("handlingName"),
                            HandlingType = (string)i.Element("handlingType"),
                            Mass = i.Element("fMass").Attribute("value").Value
                        };
            foreach (var item in query)
            {
                if (item.HandlingType == "HANDLING_TYPE_FLYING")
                {
                    //Remove messagebox if consoleapp
                    MessageBox.Show(item.HandlingType);
                    MessageBox.Show(item.HandlingName);
                    Console.WriteLine(item.HandlingType);
                    Console.WriteLine(item.HandlingName);
                }
            }
        }
    }

I would recommend looking into serializing your xml to an object.

Answer 2

If you look at http://msdn.microsoft.com/en-us/library/system.xml.linq.xelement(v=vs.110).aspx the ToString() method doesn't return the name of the tag, but the indented XML.

You should instead be using the Value property. Also you should use .equals("...") instead of ==

if (handlingType.Value.equals("HANDLING_TYPE_FLYING")
{
    messageBox.Show(this.handlingname);
}