How to get value from a specific child element in XML using XmlReader?

Question

Here's the XML string.

<?xml version="1.0" encoding="utf-16"?>
<questionresponses>
  <question id="dd7e3bce-57ee-497a-afe8-e3d8d25e2671">
    <text>Question 1?</text>
    <response>abcdefg</response>
    <correctresponse>123</correctresponse>
  </question>
  <question id="efc43b1d-048f-4ba9-9cc0-1cc09a7eeaf2">
    <text>Question 2?</text>
    <response>12345678</response>
    <correctresponse>123</correctresponse>
  </question>
</questionresponses>

So how could I get value of <response> element by given question Id? Say, if I give id value = "dd7e3bce-57ee-497a-afe8-e3d8d25e2671", I'd like to have string value abcdefg returned as result.

var xmlstr = "content from above xml example";
using (var reader = XmlReader.Create(new StringReader(xmlstr)))
{
    while(reader.Read())
    {
        if(reader.IsStartElement())
        {
            var attr = reader["id"];
            if(attr != null && attr == "dd7e3bce-57ee-497a-afe8-e3d8d25e2671")
            {
                if(reader.ReadToDescendant("response"))
                {
                    result = reader.Value; // <= getting empty string? So what's wrong?
                    break;
                }
            }
        }
    }
}

Pranay Rana · Accepted Answer · 2013-09-19 09:57:41Z

26

you might need to do like this , problem i think is reader is not moving to text and because of that you are getting empty

        if(reader.ReadToDescendant("response"))
            {
                reader.Read();//this moves reader to next node which is text 
                result = reader.Value; //this might give value than 
                break;
            }

Above one is working for me you can try out at your end

edited Sep 19, 2013 at 9:57

answered Sep 19, 2013 at 9:51

Pranay Rana

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2 Comments

woodykiddy Over a year ago

Yeah, indeed, I was missing out reader.Read() which is why reader.Value is empty. Thanks for point this out quickly.

Corey Over a year ago

Do we need break; here?

Anirudha · Accepted Answer · 2013-09-19 10:01:53Z

6

I would use LINQ2XML..

XDocument doc=XDocument.Parse(xmlstr);
String response=doc.Elements("question")
                   .Where(x=>x.Attribute("id")==id)
                   .Single()
                   .Element("response")
                   .Value;

edited Sep 19, 2013 at 10:01

answered Sep 19, 2013 at 9:55

Anirudha

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Comments

Nick Volynkin · Accepted Answer · 2015-07-02 00:00:48Z

1

if (reader.NodeType == XmlNodeType.Element)
{
    if(reader.Name == "response")
    {
        reader.read();
        var res = reader.Value;
    }
}

//it works for me !!!!

edited Jul 2, 2015 at 0:00

Nick Volynkin

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answered Jul 1, 2015 at 18:43

gustavo ortega

111 bronze badge

Comments

Community · Accepted Answer · 2019-06-26 11:00:48Z

You can use this function to get a response for specific questions from XML stored in QuestionXML.xml.

private string getResponse(string questionID)
            {
                string response = string.Empty;
                using (StreamReader sr = new StreamReader("QuestionXML.xml", true))
                {
                    XmlDocument xmlDoc1 = new XmlDocument();
                    xmlDoc1.Load(sr);
                    XmlNodeList itemNodes = xmlDoc1.GetElementsByTagName("question");
                    if (itemNodes.Count > 0)
                    {
                        foreach (XmlElement node in itemNodes)
                        {
                            if (node.Attributes["id"].Value.ToString() == questionID.Trim())
                            {
                                response = node.SelectSingleNode("response").InnerText;
                                break;
                            }

                        }
                    }
                }
                return response;
            }

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