介绍

QAssociativeIterable类是QVariant中一个关联式容器的可迭代接口。这个类允许多种访问在QVariant中保存的关联式容器元素的方法。如果一个QVariant可以转换为QVariantHash或QVariantMap，那么QAssociativeIterable的实例可以从中提取出来。

QHash<int, QString> mapping;mapping.insert(7, "Seven");mapping.insert(11, "Eleven");mapping.insert(42, "Forty-two");QVariant variant = QVariant::fromValue(mapping);if (variant.canConvert<QVariantHash>()) {QAssociativeIterable iterable = variant.value<QAssociativeIterable>();// Can use foreach over the values:foreach (const QVariant &v, iterable) {qDebug() << v;}// Can use C++11 range-for over the values:for (const QVariant &v : iterable) {qDebug() << v;}// Can use iterators:QAssociativeIterable::const_iterator it = iterable.begin();const QAssociativeIterable::const_iterator end = iterable.end();for ( ; it != end; ++it) {qDebug() << *it; // The current valueqDebug() << it.key();qDebug() << it.value();}}

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