LINQ to XML：不要获取XElement

Question

it should be easy but I don't really see my fault.

public static void Edit(string old, string neew, string type)
    {
        XElement root = XElement.Load(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\Xml.xml");

        switch (type)
        {
            case "Customer":

                XElement name = root.Descendants("Data").Descendants("Customer")
                    .Where(x => x.Element("Name").Value.ToString() == old)
                    .FirstOrDefault();

                name.SetElementValue("Name", neew);
                break;

XElement name returns null, so I get a NullReferenceException. But I don't know, why it only returns null.

This is my Xml structure:

<Data>   
            <Customer>
                <Name>CustomerA</Name>
                <IP>888.888.888.888</IP>
                <UserLogin>auser</UserLogin>
                <UserPw>apwd</UserPw>   
            </Customer>   
            <Customer>
                <Name>CustomerB</Name>
                <IP>102.16.70.181</IP>
                <UserLogin>buser</UserLogin>
                <UserPw>bpwd</UserPw>   
            </Customer> 
        </Data>

Maybe someone could open my eyes and help me? Or give a hint?

Answer 1

it seems Data is already your root element. You can use root.Elements("Customer") or root.Descendants("Customer") instead.

Apart from that XElement.Value property is of type string , so you don't need to call ToString on it.Also you may consider using explicit casts like (string)x.Element("Name") == old to avoid exceptions if the elements isn't found.