<![CDATA[Get inherited QTreeWidgetItem]]>Hi!
I inherited in QTreeWidgetItem and set this item to QTreeWidget. How I can get MyTreeWidgetItem from QTreeWidget in signal currentItemChanged and function currentItem()?

class MyTreeWidgetItem : public QObject, public QTreeWidgetItem
{
    Q_OBJECT
public:
    MyTreeWidgetItem(){};
    int id = -1;
    int type = TypeItemProtocol::protocol;
    QVector <int> vector;
    void setId(int value){id = value;}
    int  getId(){return id;}
    void setType(int typeValue) {type = typeValue;}
    int  getType() {return type;}
    void addInVector(int value) {vector.append(value);}
};
]]>https://forum.qt.io/topic/139514/get-inherited-qtreewidgetitemRSS for NodeFri, 06 Nov 2026 10:05:25 GMTFri, 23 Sep 2022 08:48:16 GMT60<![CDATA[Reply to Get inherited QTreeWidgetItem on Fri, 23 Sep 2022 09:40:46 GMT]]>@Christian-Ehrlicher said in Get inherited QTreeWidgetItem:

or qobject_cast<>

=> qobject_cast<MyTreeWidgetItem*>(current);

Here MyTreeWidgetItem is QObject but current's formal type is QTreeWidgetItem, which is not QObject. In this situation is qobject_cast<> allowed?

]]>https://forum.qt.io/post/729915https://forum.qt.io/post/729915Fri, 23 Sep 2022 09:40:46 GMT<![CDATA[Reply to Get inherited QTreeWidgetItem on Fri, 23 Sep 2022 09:41:39 GMT]]>@jsulm said in Get inherited QTreeWidgetItem:

If cast fails because the object is not MyTreeWidgetItem you will get nullptr

True for dynamic_cast<>. The only time OP's static_cast<> would return nullptr is if QTreeWidgetItem *current == nullptr, not if it were say plain QTreeWidgetItem *. Just saying.....

]]>https://forum.qt.io/post/729914https://forum.qt.io/post/729914Fri, 23 Sep 2022 09:41:39 GMT<![CDATA[Reply to Get inherited QTreeWidgetItem on Fri, 23 Sep 2022 09:37:16 GMT]]>@jsulm said in Get inherited QTreeWidgetItem:

You should always check pointers after casts!

... and use the correct cast - static_cast<> is very problematic here since you can't huarantee that every item is a MyTreeWidgetItem here. Use dynamic_cast<> or qobject_cast<>

]]>https://forum.qt.io/post/729913https://forum.qt.io/post/729913Fri, 23 Sep 2022 09:37:16 GMT<![CDATA[Reply to Get inherited QTreeWidgetItem on Fri, 23 Sep 2022 09:27:42 GMT]]>@Mihaill You should always check pointers after casts! If cast fails because the object is not MyTreeWidgetItem you will get nullptr and your app will crash if you try to use it.

]]>https://forum.qt.io/post/729908https://forum.qt.io/post/729908Fri, 23 Sep 2022 09:27:42 GMT<![CDATA[Reply to Get inherited QTreeWidgetItem on Fri, 23 Sep 2022 09:12:01 GMT]]>It is work

void MainWindow::on_treeWidgetSession_currentItemChanged(QTreeWidgetItem *current, QTreeWidgetItem *previous)
{
    MyTreeWidgetItem* item = static_cast<MyTreeWidgetItem*>(current);
]]>https://forum.qt.io/post/729903https://forum.qt.io/post/729903Fri, 23 Sep 2022 09:12:01 GMT<![CDATA[Reply to Get inherited QTreeWidgetItem on Fri, 23 Sep 2022 08:50:45 GMT]]>@Mihaill Simply cast QTreeWidgetItem* to MyTreeWidgetItem*

]]>https://forum.qt.io/post/729899https://forum.qt.io/post/729899Fri, 23 Sep 2022 08:50:45 GMT