QTreeWidget에 Combobox 추가,삭제 방법

추가
QTreeWidgetItem* item= new QTreeWidgetItem(ui->treeWidget); 
QComboBox *Combobox=new QComboBox();
//setItemWidget 인자설명
//1.TreewidgetItem,2.추가할 컬럼, 3.추가할위젯
ui->treeWidget->setItemWidget(item,0,Combobox);

삭제
//Toplevel에서의 삭제 = 0은 Toplevel의 맨처음 아이템
//Child를 삭제하려면, topLevelItem(0)->child(0)을 추가하면된다.
QTreeWidgetItem* item= ui->treeWidget->topLevelItem(0) ;
//1.TreewidgetItem, 2. 삭제할 컬럼
ui->treeWidget->removeItemWidget(item,0);

Combobox 데이터 추가
for(int i=0; i<ui->treeWidget->topLevelItemCount(); i++)

{
     for(int j=0; j<ui->treeWidget->topLevelItem(i)->childCount(); j++)
     {
          QTreeWidgetItem *testItem=ui->treeWidget->topLevelItem(i)->child                                                     (j);
          auto Combobox=(QComboBox*)ui->treeWidget->itemWidget                                               (testItem,0);
               for(int k=0; k<ui->treeWidget->topLevelItem(i)->childCount(); k++)
               {                  
                    Combobox->addItem(ui->treeWidget->topLevelItem(i)->child                     (k)->text(1));
               }
       }
}