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Update combobox data from model

  • I have a categories QComboBox which is linked to a QSqlTableModel. Also I have a second window to manage categories (add/remove). How to update/refresh/reload the combobox whenever a category is added/removed?

    My code:

    int catIndex = model2->fieldIndex("category");
    model2->setRelation(catIndex, QSqlRelation("categories", "id", "name"));
    QSqlTableModel *catModel = model2->relationModel(catIndex);
    mapper->addMapping(ui->comboBox_2, catIndex);

  • Hi @rudag

    after adding/removing in your second window send a signal to a slot of the object where you call "your code" and in the slot call "your code" again.


  • Lifetime Qt Champion


    How are you adding / removing these categories ?

  • @m-sue
    I can call the main window from the categories window. Problem is I don't know the code to reload the QComboBox.

    It's another window which has a QTableView with a QSqlTableModel linked to the categories table.

  • Hi @rudag

    I do not understand. You wrote the code in your first post. Just call it again. Then the changed model should refill the combobox.

    If you want the model to update your combobox, though, you will probably have to derive your own model class and override the functions for update and remove of data sets.


  • @m-sue
    I'm getting the following error when I try to call that piece of code more than once:
    QComboBox::setModel: cannot set a 0 model

  • Lifetime Qt Champion

    Then why not share the model between the widgets ?

  • I did this:


    And it's working!

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