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Combobox in Qtableview

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  • N n-2204

    @VRonin @mrjj
    1.
    Actually when I'm using both the ways to add values in Combobox
    one thing happening ,if I added some values in column0 table1 then select in combobox and again adding values in table1 Column0 that time combobox selection go away

    I am using dataChanged() signal
    connect(ui.tableView->model(), &QAbstractItemModel::dataChanged, this,
    &tool::rowvalue1);
    Is it because of this signal ? how can i prevent this ??

    1. As I'm using SLOT::rowvalue1() to add combobox in Qtableview
      now how can i take index() of combobox as there is SIGNAL::QComboBox::currentIndexChanged, , so again I need to write SLOT for index
      void tool::IndexChanged(int index)
      {
      combo->setCurrentIndex(combo->currentIndex());
      //but combo will be inaccessible here ??
      }
      connect(combo, QOverload<int>::of(&QComboBox::currentIndexChanged), this,
      &tool::IndexChanged);
      Is this correct way ?
    VRoninV Offline
    VRoninV Offline
    VRonin
    wrote on last edited by VRonin
    #29

    @n-2204 said in Combobox in Qtableview:

    Is it because of this signal ? how can i prevent this ??

    It's because you recreate the entire list every time. You should just add/remove only the items that changed


    You can use std::bind to forward the combo to the slot

    void IndexChanged(int index, QComboBox* combo){
    /// do stuff
    }
    

    connect(combo, QOverload<int>::of(&QComboBox::currentIndexChanged), this, std::bind(&tool::IndexChanged, this, std::placeholders::_1, combo));

    "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
    ~Napoleon Bonaparte

    On a crusade to banish setIndexWidget() from the holy land of Qt

    1 Reply Last reply
    1
    • N Offline
      N Offline
      n-2204
      wrote on last edited by n-2204
      #30

      @VRonin
      It's because you recreate the entire list every time. You should just add/remove only the items that changed
      okay,, ya I'm using dataChanged signal , so i think whenever changes in table1 col0 values so combobox selection got affect

      connect(ui.tableView->model(), &QAbstractItemModel::dataChanged, this,
      &tool::rowvalue1);
      

      So need to change in SIGNAL or anycondition to be add?
      but I need to update data in combobox so datachanged signal must be used.
      need to give condition in combobox ? or in SLOT something need to change or what else ??

      VRoninV 1 Reply Last reply
      0
      • N n-2204

        @VRonin
        It's because you recreate the entire list every time. You should just add/remove only the items that changed
        okay,, ya I'm using dataChanged signal , so i think whenever changes in table1 col0 values so combobox selection got affect

        connect(ui.tableView->model(), &QAbstractItemModel::dataChanged, this,
        &tool::rowvalue1);
        

        So need to change in SIGNAL or anycondition to be add?
        but I need to update data in combobox so datachanged signal must be used.
        need to give condition in combobox ? or in SLOT something need to change or what else ??

        VRoninV Offline
        VRoninV Offline
        VRonin
        wrote on last edited by
        #31

        Instead of just doing

        combo->model()->removeRows(0,combo->count(),combo->rootModelIndex()); // remove all items from the combo
        combo->addItems(guesslist);  //add list to combobox
        

        iterate over the items in the combo, remove those that don't appear in guesslist and add those that appear in guesslist but are not already in the combo

        "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
        ~Napoleon Bonaparte

        On a crusade to banish setIndexWidget() from the holy land of Qt

        1 Reply Last reply
        1
        • N Offline
          N Offline
          n-2204
          wrote on last edited by
          #32

          to remove duplicates

          guesslist.removeDuplicates(); // clear duplicates
          guesslist.removeAll(QString(""));
          combo->model()->removeRows(0,combo->count(),combo->rootModelIndex()); // remove all items from the combo
          combo->addItems(guesslist);  //add list to combobox
          

          remove those that don't appear in guesslist
          --means using removerows() all items are removed everytime so this need to change ??

          VRoninV 1 Reply Last reply
          0
          • N n-2204

            to remove duplicates

            guesslist.removeDuplicates(); // clear duplicates
            guesslist.removeAll(QString(""));
            combo->model()->removeRows(0,combo->count(),combo->rootModelIndex()); // remove all items from the combo
            combo->addItems(guesslist);  //add list to combobox
            

            remove those that don't appear in guesslist
            --means using removerows() all items are removed everytime so this need to change ??

            VRoninV Offline
            VRoninV Offline
            VRonin
            wrote on last edited by
            #33

            @n-2204 said in Combobox in Qtableview:

            all items are removed everytime so this need to change ??

            Correct

            "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
            ~Napoleon Bonaparte

            On a crusade to banish setIndexWidget() from the holy land of Qt

            N 1 Reply Last reply
            0
            • VRoninV VRonin

              @n-2204 said in Combobox in Qtableview:

              all items are removed everytime so this need to change ??

              Correct

              N Offline
              N Offline
              n-2204
              wrote on last edited by
              #34

              @VRonin Is removeItem() can be used ?

              1 Reply Last reply
              1
              • N Offline
                N Offline
                n-2204
                wrote on last edited by
                #35

                @VRonin said in Combobox in Qtableview:
                for (int r = 0, maxI = table1->rowCount(); r < maxI; ++r) { //for all value rows
                guesslist.append( table1->data(table1->index(r, 0)).toString() );//store value in stringlist
                }

                guesslist is always updated,

                for (int i = 0, maxI = table2->rowCount(); i < maxI; ++i)//for all rows
                    {
                        const QModelIndex idx = table2->index(i, 1);
                        QComboBox* combo = qobject_cast<QComboBox*>(ui.tableView_2->indexWidget(idx));
                        if (!combo)
                          {
                            combo = new QComboBox(); // make combo  
                            ui.tableView_2->setIndexWidget(idx, combo);// add combo
                        }
                        colvallist1.removeDuplicates(); // strip dubs clear dublicates
                        colvallist1.removeAll(QString(""));
                        combo->setPlaceholderText(QString(" "));
                
                        combo->addItems(guesslist); // adding gueslist will add item value everytime so no need to pass this right ??
                combo->removeItem(); 
                

                iterate over the items in the combo, remove those that don't appear in guesslist and add those that appear in guesslist but are not already in the combo

                item should store in another Qstringlist and then check with initial list ?

                1 Reply Last reply
                0
                • N Offline
                  N Offline
                  n-2204
                  wrote on last edited by n-2204
                  #36

                  edited
                  In prev code i add these code lines, and now selection not changed when added new items in tableview column and updating in col combobox values

                   for (int i = 0; i < guesslist.count(); i++) 
                          {
                              if (combo->findText(guesslist[i]) != -1)//-1 means "not found"
                              { 
                                  continue;
                              }
                              else {
                                  combo->addItem(guesslist[i]); //Add to QCombobox
                              }
                  

                  but not able to apply for "remove those t don't appear in guesslist (when col1 row values chnaged)" ??

                  JonBJ 1 Reply Last reply
                  0
                  • N n-2204

                    edited
                    In prev code i add these code lines, and now selection not changed when added new items in tableview column and updating in col combobox values

                     for (int i = 0; i < guesslist.count(); i++) 
                            {
                                if (combo->findText(guesslist[i]) != -1)//-1 means "not found"
                                { 
                                    continue;
                                }
                                else {
                                    combo->addItem(guesslist[i]); //Add to QCombobox
                                }
                    

                    but not able to apply for "remove those t don't appear in guesslist (when col1 row values chnaged)" ??

                    JonBJ Offline
                    JonBJ Offline
                    JonB
                    wrote on last edited by
                    #37

                    @n-2204
                    So you have to one of:

                    • Have another loop/iterator through all the items which are in the combo box and remove any which are not in the guess list now; or
                    • Clear out all the items in the combo box first, and then only add back in those which are now in guess list.
                    N 1 Reply Last reply
                    1
                    • JonBJ JonB

                      @n-2204
                      So you have to one of:

                      • Have another loop/iterator through all the items which are in the combo box and remove any which are not in the guess list now; or
                      • Clear out all the items in the combo box first, and then only add back in those which are now in guess list.
                      N Offline
                      N Offline
                      n-2204
                      wrote on last edited by n-2204
                      #38

                      @JonB said in Combobox in Qtableview:

                      Clear out all the items in the combo box first, and then only add back in those which are now in guess list.

                      when i'm clearing all first then, whatever my prev selection in combobox it will be gone 
                       combo->clear();
                      

                      Have another loop/iterator through all the items which are in the combo box and remove any which are not in the guess list now

                      tried this but not working correctly where to chnge ?,when I'm changing value in guesslist then the combo selection got changed

                        QStringList itemsInComboBox;
                                  for (int index = 0; index < guesslist.count(); index++)
                                  {
                                      itemsInComboBox << combo->itemText(index);
                                      if ( guesslist[index]!=itemsInComboBox[index] )
                                          combo->removeItem(index); 
                                  }
                      
                      JonBJ 1 Reply Last reply
                      0
                      • N n-2204

                        @JonB said in Combobox in Qtableview:

                        Clear out all the items in the combo box first, and then only add back in those which are now in guess list.

                        when i'm clearing all first then, whatever my prev selection in combobox it will be gone 
                         combo->clear();
                        

                        Have another loop/iterator through all the items which are in the combo box and remove any which are not in the guess list now

                        tried this but not working correctly where to chnge ?,when I'm changing value in guesslist then the combo selection got changed

                          QStringList itemsInComboBox;
                                    for (int index = 0; index < guesslist.count(); index++)
                                    {
                                        itemsInComboBox << combo->itemText(index);
                                        if ( guesslist[index]!=itemsInComboBox[index] )
                                            combo->removeItem(index); 
                                    }
                        
                        JonBJ Offline
                        JonBJ Offline
                        JonB
                        wrote on last edited by JonB
                        #39

                        @n-2204 said in Combobox in Qtableview:

                        when i'm clearing all first then, whatever my prev selection in combobox it will be gone
                        combo->clear();

                        Yes, and, so? If you want to preserve what was selected, note it and reselect.

                        Your loop for removing is no good. For one thing, you only check the same index in both guess list and combo box. If you do not clear the items, implement what I wrote:

                        Have another loop/iterator through all the items which are in the combo box and remove any which are not in the guess list now

                        That is just basic algorithmic stuff.

                        N 1 Reply Last reply
                        0
                        • JonBJ JonB

                          @n-2204 said in Combobox in Qtableview:

                          when i'm clearing all first then, whatever my prev selection in combobox it will be gone
                          combo->clear();

                          Yes, and, so? If you want to preserve what was selected, note it and reselect.

                          Your loop for removing is no good. For one thing, you only check the same index in both guess list and combo box. If you do not clear the items, implement what I wrote:

                          Have another loop/iterator through all the items which are in the combo box and remove any which are not in the guess list now

                          That is just basic algorithmic stuff.

                          N Offline
                          N Offline
                          n-2204
                          wrote on last edited by n-2204
                          #40

                          @JonB

                          Have another loop/iterator through all the items which are in the combo box and remove any which are not in the guess list now

                          I tired this but not working correctly.. now if item in guesslist then also it got removed ???

                           QStringList itemsInComboBox;
                               for (int index = 0; index < guesslist.count(); ++index) {  //check in list
                                  for (int item = 0; item < combo->count(); ++item) {  //check in combobox
                                      itemsInComboBox << combo->itemText(item);
                                      qDebug() << "before remove " << itemsInComboBox;
                                                if ( guesslist[index] != itemsInComboBox[item]  )
                                                combo->removeItem(item);
                                      }
                                  }
                          
                          N 1 Reply Last reply
                          0
                          • N n-2204

                            @JonB

                            Have another loop/iterator through all the items which are in the combo box and remove any which are not in the guess list now

                            I tired this but not working correctly.. now if item in guesslist then also it got removed ???

                             QStringList itemsInComboBox;
                                 for (int index = 0; index < guesslist.count(); ++index) {  //check in list
                                    for (int item = 0; item < combo->count(); ++item) {  //check in combobox
                                        itemsInComboBox << combo->itemText(item);
                                        qDebug() << "before remove " << itemsInComboBox;
                                                  if ( guesslist[index] != itemsInComboBox[item]  )
                                                  combo->removeItem(item);
                                        }
                                    }
                            
                            N Offline
                            N Offline
                            n-2204
                            wrote on last edited by
                            #41

                            Hi,
                            adding those that appear in guesslist code-

                            for (int i = 0; i < guesslist.count(); i++) 
                                {
                                    if (combo->findText(guesslist[i]) != -1)//-1 means "not found"
                                    { 
                                        continue;
                                    }
                                    else {
                                        combo->addItem(guesslist[i]); //Add to QCombobox
                                    }
                            

                            ///remove which are not in the guess list code below I tried multiple times but this is not working correctly ? I don't want to change my selection when any item added / removed / replaced ..Plz help😞

                            QStringList itemsInComboBox;
                             for (int index = 0; index < guesslist.count(); ++index) {  //check in list
                                for (int item = 0; item < combo->count(); ++item) {  //check in combobox
                                    itemsInComboBox << combo->itemText(item);
                                    qDebug() << "before remove " << itemsInComboBox;
                                              if ( guesslist[index] != itemsInComboBox[item]  )
                                              combo->removeItem(item);
                                    }
                                 }
                            

                            Thanks in advance

                            1 Reply Last reply
                            0
                            • N Offline
                              N Offline
                              n-2204
                              wrote on last edited by
                              #42

                              Have another loop/iterator through all the items which are in the combo box and remove any which are not in the guess list now

                              for me this way is not working any how selection of combobox is going away..
                              how can i store the selection of combobox ?

                              artwawA JonBJ 2 Replies Last reply
                              0
                              • N n-2204

                                Have another loop/iterator through all the items which are in the combo box and remove any which are not in the guess list now

                                for me this way is not working any how selection of combobox is going away..
                                how can i store the selection of combobox ?

                                artwawA Offline
                                artwawA Offline
                                artwaw
                                wrote on last edited by
                                #43

                                @n-2204 https://doc.qt.io/qt-5/qcombobox.html#currentIndex-prop or currentText() if you can't relay on the order of the items or itemData() if you use roles, later on you can find the same text with different index, if that's the case, using findText() or findData().

                                Do you read any documentation at all? It's all there in clear text.

                                For more information please re-read.

                                Kind Regards,
                                Artur

                                N 1 Reply Last reply
                                1
                                • N n-2204

                                  Have another loop/iterator through all the items which are in the combo box and remove any which are not in the guess list now

                                  for me this way is not working any how selection of combobox is going away..
                                  how can i store the selection of combobox ?

                                  JonBJ Offline
                                  JonBJ Offline
                                  JonB
                                  wrote on last edited by JonB
                                  #44

                                  @n-2204
                                  The whole thing, for what I think you say you want:

                                  QString selected = combo->currentText();
                                  combo->clear();
                                  combo->addItems(guesslist);
                                  combo->setCurrentText(selected);
                                  
                                  N 1 Reply Last reply
                                  0
                                  • JonBJ JonB

                                    @n-2204
                                    The whole thing, for what I think you say you want:

                                    QString selected = combo->currentText();
                                    combo->clear();
                                    combo->addItems(guesslist);
                                    combo->setCurrentText(selected);
                                    
                                    N Offline
                                    N Offline
                                    n-2204
                                    wrote on last edited by n-2204
                                    #45

                                    @JonB said in Combobox in Qtableview:

                                    The whole thing, for what I think you say you want:

                                    QString selected = combo->currentText();
                                    combo->clear();
                                    combo->addItems(guesslist);
                                    combo->setCurrentText(selected);
                                    edited
                                    thanks it works,, there some other mistake in code

                                    1 Reply Last reply
                                    0
                                    • artwawA artwaw

                                      @n-2204 https://doc.qt.io/qt-5/qcombobox.html#currentIndex-prop or currentText() if you can't relay on the order of the items or itemData() if you use roles, later on you can find the same text with different index, if that's the case, using findText() or findData().

                                      Do you read any documentation at all? It's all there in clear text.

                                      N Offline
                                      N Offline
                                      n-2204
                                      wrote on last edited by
                                      #46

                                      @artwaw said in Combobox in Qtableview:
                                      currentText() if you can't relay on the order of the items or itemData() if you use roles, later on you can find the same text with different index, if that's the case, using findText() or findData().

                                      Do you read any documentation at all? It's all there in clear text.

                                      Thanks,,i trying to implement but thing is removeitem+selection from combobox not working correctly

                                      JonBJ 1 Reply Last reply
                                      0
                                      • N n-2204

                                        @artwaw said in Combobox in Qtableview:
                                        currentText() if you can't relay on the order of the items or itemData() if you use roles, later on you can find the same text with different index, if that's the case, using findText() or findData().

                                        Do you read any documentation at all? It's all there in clear text.

                                        Thanks,,i trying to implement but thing is removeitem+selection from combobox not working correctly

                                        JonBJ Offline
                                        JonBJ Offline
                                        JonB
                                        wrote on last edited by
                                        #47

                                        @n-2204 said in Combobox in Qtableview:

                                        currentText() if you can't relay on the order of the items or itemData() if you use roles, later on you can find the same text with different index, if that's the case, using findText() or findData().

                                        From my code all you need to restore the selection is the combo->setCurrentText(selected);.

                                        1 Reply Last reply
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