#include <QVariant>
#include <QMetaType>
#include <QDebug>

static void checkAndConvert(QVariant &var, QMetaType toType)
{
    qDebug("");
    qDebug() << "Can convert to" << toType << "?" << var.canConvert(toType);
    qDebug() << "Conversion successful?" << var.convert(toType);
    qDebug() << "New value:" << var;
}

int main()
{
    QVariant var = QVariant::fromValue(quint8(55)); // 55 == 0x37 == ASCII representation for '7'
    QMetaType origType = var.metaType();
    qDebug() << "Original value:" << var;

    checkAndConvert(var, QMetaType(QMetaType::QString));
    checkAndConvert(var, origType);
}