qtqtxmlqdomdocument

How to concatenate QDomDocument::createElement calls?

I do use the QtXML Module providing a "nice" DOM-Model for Qt.

The problem i encounter is, one cannot concatenate the calls making one require to create extra QDomElement variables for appending. Is there a way around this?

QDomDocument doc;
QDomProcessingInstruction xmlVers = doc.createProcessingInstruction("xml","version=\"1.0\" encoding='utf-8'");
doc.appendChild(xmlVers);

QDomElement docTool = doc.createElement("tool");
doc.appendChild(docTool);

QDateTime t = QDateTime::currentDateTime();
QString dateString = t.toString("yyyy-MM-ddTHH:mm:ss");

// 0: Correct implementation requiring extra QDomElement dateElement
QDomElement dateElement = doc.createElement("date");
dateElement.appendChild(doc.createTextNode(dateString));
docTool.appendChild(dateElement);

// 1: Concatenating create* calls without extra variable
docTool.appendChild(doc.createElement("date1").appendChild(doc.createTextNode(dateString)));

// 2: Trying to encapsulate createElement call by brackets
docTool.appendChild((((QDomElement)doc.createElement("date2")).appendChild(doc.createTextNode(dateString))));

// 3: Trying to hit the nail by elementById (Broken per documentation?!)    

docTool.appendChild(doc.createElement("date3"));
doc.elementById("date3").appendChild(doc.createTextNode(dateString));

ui->textBrowser->append(doc.toString());

Giving really strange results:

<?xml version="1.0" encoding='utf-8'?>
<tool>
 <date>2015-01-21T10:33:56</date>2015-01-21T10:33:562015-01-21T10:33:56<date3/>
</tool>

As we see 0: is correct 1: has no date tag at all 2: same as before 3: has the date tag but no textnode content

Why can one not concatenate these calls?

Solution

  • appendChild() returns the node that was added. So in:

    docTool.appendChild(doc.createElement("date1").appendChild(doc.createTextNode(dateString)));

    you end up trying to append the text node to both the date1 element and the docTool element. This should work:

    docTool.appendChild(doc.createElement("date1")).appendChild(doc.createTextNode(dateString));