I'm using an API call to return some XML data from a web server. The XML data is in the following format:
<forismatic>
<quote>
<quoteText>The time you think you're missing, misses you too.</quoteText>
<quoteAuthor>Ymber Delecto</quoteAuthor>
<senderName></senderName>
<senderLink></senderLink>
<quoteLink>http://forismatic.com/en/55ed9a13c0/</quoteLink>
</quote>
</forismatic>
I can retrieve the raw XML data successfully, and I want to add the <quoteText>
and <quoteAuthor>
node values to strings but seem to be unable to do this. My current code:
private void btnGetQuote_Click(object sender, EventArgs e)
{
WebRequest req = WebRequest.Create("http://api.forismatic.com/api/1.0/");
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
string reqString = "method=getQuote&key=457653&format=xml&lang=en";
byte[] reqData = Encoding.UTF8.GetBytes(reqString);
req.ContentLength = reqData.Length;
using (Stream reqStream = req.GetRequestStream())
reqStream.Write(reqData, 0, reqData.Length);
using (WebResponse res = req.GetResponse())
using (Stream resSteam = res.GetResponseStream())
using (StreamReader sr = new StreamReader(resSteam))
{
string xmlData = sr.ReadToEnd();
txtXmlData.Text = xmlData;
Read(xmlData);
}
}
private void Read(string xmlData)
{
XDocument doc = XDocument.Parse(xmlData);
string quote = doc.Element("quote").Attribute("quoteText").Value;
string auth = doc.Element("quote").Attribute("quoteAuthor").Value;
txtQuoteResult.Text = "QUOTE: " + quote + "\r\n" + "AUTHOR: " + auth;
}
My program bombs out with An unhandled exception of type 'System.NullReferenceException' occurred while trying to set the string value quote
. I've looked at some similar posts and made various changes but can't seem to get the two string values set.
You're trying to use doc.Element("quote")
- there's no such element, so that's returning null. You'd want doc.Root.Element("quote")
. Next you're asking for quoteText
and quoteAuthor
as if they were attributes - they're not, they're elements too.
So basically you want:
private void Read(string xmlData)
{
XDocument doc = XDocument.Parse(xmlData);
XElement quote = doc.Root.Element("quote");
string text = quote.Element("quoteText").Value;
string author = quote.Element("quoteAuthor").Value;
txtQuoteResult.Text = $"QUOTE: {text}\r\nAUTHOR: {author}";
}
(I'd personally make the method return the string value and set it as txtQuoteResult.Text
within the calling method, but that's a different matter.)
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