Can I conveniently converty QVariant back to QList<MyType>?

问题

It is possible to convert QList<YourType> to QVariant provided you declare your type as q meta type using this macro:

Q_DECLARE_METATYPE(MyType);

After that, the conversion is even implicit:

QList<MyType> list;
QVariant variant = QVariant::fromValue(list);

Now my question is how to convert variant back to QList<MyType>.

回答1:

QVariant provides method canConvert<T> that you can use to check:

 if( variant.canConvert<QList<MyType>>() ) {
     QList<MyType> list = variant.value<QList<MyType>>();
     ...
 }

回答2:

Just to clearly combine what I got in comments and the accepted answer.

QList<MyType> convertToMyType(QVariant variant) {
   if( variant.canConvert<QList<MyType>>() ) {
       return variant.value<QList<MyType>>();
   }
   else {
       // Exception? Empty list?
       // depends on circumstances
   }
}

来源：https://stackoverflow.com/questions/36623931/can-i-conveniently-converty-qvariant-back-to-qlistmytype