How to retrieve element values of nested elements in XML with C#

Question

<config>
<timeDifferenceFields>
    <TimeDifference>
        <StartTimeField>txt_SoReinigungUhrzeitvonZ1</StartTimeField>
        <EndTimeField>txt_SoReinigungUhrzeitbisZ1</EndTimeField>
        <OutputTimeField>txt_SoReinigungZ1</OutputTimeField>
    </TimeDifference>
    <TimeDifference>
        <StartTimeField>txt_SoReinigungUhrzeitvonZ2</StartTimeField>
        <EndTimeField>txt_SoReinigungUhrzeitbisZ2</EndTimeField>
        <OutputTimeField>txt_SoReinigungZ2</OutputTimeField>
    </TimeDifference>
    <TimeDifference>
        <StartTimeField>txt_SoReinigungUhrzeitvonZ3</StartTimeField>
        <EndTimeField>txt_SoReinigungUhrzeitbisZ3</EndTimeField>
        <OutputTimeField>txt_SoReinigungZ3</OutputTimeField>
    </TimeDifference>
</timeDifferenceFields>
</config>

Hi,

can someone help me with this easy task, I dont get it...

I want to iterate over the TimeDifference-Fields in the above XML-File. For each TimeDifference Node I want to call a method with the given XML-Values.

With this it runs into a NPE ... can someone help please

     XmlDocument configDoc = new XmlDocument();
        configDoc.Load(configXml);

        XmlNode timeFields = configDoc.SelectSingleNode("/config/timeDifferenceFields/TimeDifference");
        foreach (XmlNode timeNode in timeFields)
        {
        String OutputTimeField = timeNode.SelectSingleNode("OutputTimeField").InnerXml;
        String StartTimeField = timeNode.SelectSingleNode("StartTimeField").InnerXml;
        String EndTimeField = timeNode.SelectSingleNode("EndTimeField").InnerXml;
        addTimeDiffElement(inputDoc, OutputTimeField, StartTimeField, EndTimeField);
        }

Answer 1

SelectSingleNode returns (as the name suggests) not more than one node. Try XmlNodeList timeFields = configDoc.SelectNodes("/config/timeDifferenceFields/TimeDifference") instead.