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c++xmlqtxmlwriter

Qt update single XML Element

I want to update a single XML element in Qt v5.0.2.

Lets say this is my XML File:

<?xml version="1.0" encoding="utf-8"?>
<root>
    <myValue1 value="1" />
    <myValue2 value="2" />
</root>

I want to update the XML element myValue and set the value to 2.

<?xml version="1.0" encoding="utf-8"?>
<root>
    <myValue1 value="2" />
    <myValue2 value="2" />
</root>

How can I proceed in Qt with this issue? Certainly, I can create a QXmlStreamWriter and write the complete XML(all 4 data lines), but I want to do something small and smart.

Solution

  • Use QDomDocument:

    QDomDocument doc;
doc.setContent(<your xml>);

QDomNodeList elems = doc.elementsByTagName("myValue1");
if (!elems.isEmpty())
{
    QDomElement el = elems.at(0).toElement();
    if (!el.isNull())
    {
        if (el.hasAttribute("value"))
        {
            el.setAttribute("value", "2");
        }
    }
}

qDebug() << doc.toString();