I'm writing phone book software(for educational purposes) I have 1 tableView,one QStandardItemModel,4 buttons(add,edit,delete,clear all)
here is a picture:
Capture.JPG

add button works correctly. But Edit button doesn't work correctly,as I want.
I add one person's number with Add button and then when I want to edit contact,I press edit Button but suddenly it crashes.
Capture.JPG

But,when I add new contact directly in tableView without add button, and then press Edit. That works. I can edit contact without any problems.
Capture.JPG
So,problem is when new contact is added via Add button. I can't see what is the problem.
source code of add and edit buttons

Qt Code: 
  1. void MainWindow::on_pushButtonAdd_clicked()
  2. {
  3.     ChangeDialog dg;
  4.     dg.setWindowTitle(tr("Add new contact"));
  6.     if(dg.exec() == QDialog::Accepted){
  7.         list << dg.GetList();
  8.         for(int i = 0; i < 4;i++){
  9.             QStandardItem *item = new QStandardItem(QString("%1").arg(list.at(i)));
  10.             item->setEditable(false);
  11.             model->setItem(rowCount,i,item);
  12.         }
  13.     }
  14.     rowCount++;
  15. }
  16.  
  17. void MainWindow::on_pushButtonEdit_clicked()
  18. {
  19.     ChangeDialog dg;
  20.     dg.setWindowTitle(tr("Edit contact"));
  21.     QStringList Slist;
  22.  
  23.  
  24.     for(int i = 0; i < 4; i++){
  25.             Slist.append(model->item(rowCount,i)->text());
  26.             //QMessageBox::information(this,"title","asd");
  27.     }
  28.  
  29.     dg.SetList(Slist);
  30.     QStringList list2;
  31.     if(dg.exec() == QDialog::Accepted){
  32.         list2 << dg.GetList();
  33.         for(int i = 0; i < 4;i++){
  34.             QStandardItem *item2 = new QStandardItem(QString("%1").arg(list2.at(i)));
  35.             item2->setEditable(false);
  36.             model->setItem(rowCount,i,item2);
  37.         }
  38.     }
  39. }
To copy to clipboard, switch view to plain text mode