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Pysyde/QTableView: openPersistentEditor works only once?

  • Hi guys,
    I have a table view that has to display some comboboxes on its 5th column.
    So, on init, i set a delegate (previewModeDelegate) and draw some comboboxes:

    def initComboBoxes(self):
        model = self.view.model()
        self.view.setItemDelegateForColumn(4,  previewModeDelegate(self))
        for r in range(model.rowCount()):
            res = self.view.openPersistentEditor(model.index(r, 4))

    the delegate:

    class previewModeDelegate(QItemDelegate):
        def __init__(self, parent):
            QItemDelegate.__init__(self, parent)
            self.items = []
            self.items.append("No FX")
            self.items.append("Motion Blur")
            self.parent = parent
        def createEditor(self, parent, option, index):
            self.editor = QComboBox(parent)
            for i in range(len(self.items)):
            # getting node, getting the data 
            cNode = index.model().cameraData[index.row()]
            value = cNode.GetProperty("previewMode")
            self.editor.connect(self.editor, SIGNAL("currentIndexChanged(int)"), self.cbCallback)
            return self.editor
        def cbCallback(self, value):
            editor = self.sender()
            self.parent.view.closeEditor(editor, QAbstractItemDelegate.NoHint)
        def setModelData(self, editor, model, index):
            value = editor.currentIndex()
            # getting the node, setting the data
            cNode = model.cameraData[index.row()]
            cNode.SetProperty("previewMode", value)
            return True

    everything works fine, i get some nice working comboboxes:


    problem is. during the sw usage, i have to reset the model and recreate the comboboxes.
    So, in the gui init, i connected the InitComboBoxes method to the the resetModel signal


    After i reset the model, the initComboBoxes method is launched but the comboboxes are not reinitialized correctly:


    I am still very new to Pyside MVC. I tried tinkering with the code, but with no results. Any help?


  • Lifetime Qt Champion


    Did you check the size of the model when initComboBoxes is called ?
    If it's valid, can you try not replacing the delegate ?

  • @dammilo
    I use PyQt, but pretty similar to PySide. This probably has nothing to do with your problem, but...

    self.parent = parent

    QItemDelegate inherits all the way from QObject.parent() method. Is it a good idea to create an instance attribute with the same name as an inherited method?

    In your code, you could get rid of that anyway and simply use the existing parent() method instead. You won't need your own parent attribute in any of your classes deriving from QObject.

  • thank you guys for your inputs

    hi, i checked and the model looks always valid to me.
    My impression is that on a model level everything works - in fact, the numbers that i see on the combobox column are coming straight out of it.
    Also, I just noticed that if i double click the cell and go into edit mode, I still get my combobox delegate and I can correctly edit the values; the combobox disappears as soon as i'm done with the edit.

    I tried moving the setItemDelegateForColumn method around - only in init, after the openPersistentEditor, before it, duplicated...but no luck

    good call, didn't know that, I fixed it. But sadly, as you said, that didn't solve the issue

  • Breakthrough!

    If I connect the rebuild function to a custom signal that I emit just after the endResetModel(), everything works.

    Why is that?
    Maybe the modelReset signal is not emitted when I expect it to?

  • Lifetime Qt Champion

    modelReset should be emit after endResetMode.

    What version of PySide are you using ?

  • @SGaist sorry if I'm so late, I wasn't notified about your post.
    I'm using PySide 1.2. I am working inside 3dsmax 2017 and I have to use what Autodesk provides me - I have no choice about this.

  • I was facing exactly the same problem with PyQt5.
    I was creating a QTableView and assigned a QStyledItemDelegate to one of the columns and opened the persistent editor for the column items.
    Whenever I was programmatically adding a new row and reopening the persistent editor for all table rows, the tableview data did not change upon selecting a new item in the QComboBox of the item delegate.
    It took me a while to figure out that persistent editor was actually behaving as expected for the very last row of the table.
    I'm pretty sure that when opening the peristent editor after having added a row to the table, a second QComboBox is drawn ontop of the already existing ones in rows 0:(numberOfRowsOfOriginalTable).

    I've been able to solve the problem by effectively closing the existing persistent editors and reopening them again for all rows of the updated table.

    Nevertheless, I would expect PyQt to ignore the openPersistentEditor() command on rows where the persistent editor is already open or to give out an error message.

  • Lifetime Qt Champion

    @Almoedi hi and welcome to devnet,

    Thanks for the detailed analysis and solution !

    Would it be possible for you to provide a minimal script showing the persistant editor issue ?

  • @SGaist sorry, it took me a while to create the mwe. Here you are:

    #!/usr/bin/env python3
    # -*- coding: utf-8 -*-
    import sys
    from PyQt5.QtCore import (Qt, QAbstractTableModel, pyqtSlot)
    from PyQt5.QtWidgets import (QLabel, QTextEdit, QApplication,
                                 QStyledItemDelegate, QComboBox, QMainWindow, 
                                 QTableView, QFormLayout, QPushButton, QWidget,
                                 QHBoxLayout, QCheckBox)
    import copy
    class ComboDelegate(QStyledItemDelegate):
        def __init__(self, parent, items):
            self.items = items
            QStyledItemDelegate.__init__(self, parent)
        def createEditor(self, parent, option, index):
            self.editor = QComboBox(parent)
            font = self.editor.font()
            self.editor.setStyleSheet("background-color: white;\n"
                                      "border: 1px solid gray;\n"
                                      "padding: 1px 3px 1px 3px;")
            return self.editor
        def setEditorData(self, editor, index):
            editor.blockSignals(True) # block signals that are not caused by the user
            value =
            if value == "":
                editor.setStyleSheet("background-color: red")
                editor.setStyleSheet("background-color: white")
            num = self.items.index(value)
            if index.column() == 1:
        def setModelData(self, editor, model, index):
            model.setData(index, editor.currentText())
        def updateEditorGeometry(self, editor, option, index):
        def currentIndexChanged(self):
    class tableModel(QAbstractTableModel):
        def __init__(self, table_data = [['', '', '', '', '']]):
            self.table_data = table_data
            self.no_columns = 5
        def addRow(self, rowNbr, rowData):
            if rowNbr == -1:
                self.table_data.insert(rowNbr, rowData)
        def deleteRow(self, rowNbr):
        def data(self, index, role=Qt.DisplayRole):
            if not index.isValid():
                return None
            value = self.table_data[index.row()][index.column()]
            if role == Qt.EditRole:
                return value
            if role == Qt.DisplayRole:    
                if isinstance(value, float):
                    # Render float to 2 dp
                    return "%.2f" % value
                    return value
            if role == Qt.TextAlignmentRole:
                if index.column() in [0, 1, 2]:
                    return Qt.AlignVCenter + Qt.AlignLeft
                    return Qt.AlignVCenter + Qt.AlignRight
        def rowCount(self, index):
            return len(self.table_data)
        def columnCount(self, index):
            return self.no_columns
        def headerData(self, section, orientation, role):
            if role != Qt.DisplayRole:
                return None
            if orientation == Qt.Horizontal:
                return ("Type", "ID", "Location", "Offset T [\xB0C]", 
                        "Offset RH [%]")[section]
                return "{}".format(section)
        def setData(self, index, value, role=Qt.EditRole):
            if index.isValid():
                self.table_data[index.row()][index.column()] = value
                self.dataChanged.emit(index, index, [Qt.DisplayRole])
                return True
                return False
        def flags(self, index):
            return Qt.ItemIsEditable | Qt.ItemIsEnabled | Qt.ItemIsSelectable
    class Main(QMainWindow):
        def __init__(self):
            self.central_widget = QWidget()
            fbox = QFormLayout()
            hbox = QHBoxLayout()
            self.table = QTableView()
            self.label = QLabel('Current table data as python list')
            self.tedit = QTextEdit()
            self.applyFixCheckBox = QCheckBox('Apply fix (close and reopen '
                                              + 'persistent editor. To be checked '
                                              + 'right after program start in '
                                              + 'this example)')
            self.addRowBtn = QPushButton('Add row')
            self.deleteRowBtn = QPushButton("Delete row")
            data = [['Option2', 'Teststring', 'Testlocation', 1, 2],
                    ['Option1', 'Teststring', 'Testlocation', 0, 0]]
            self.model = tableModel(data)
            self.lastTableData = []
        def tableChanged(self):
            if self.model.table_data != self.lastTableData:
                self.lastTableData = copy.deepcopy(self.model.table_data)       
        def setComboBoxes(self):
            self.table.setItemDelegateForColumn(0, ComboDelegate(self, 
                                                                       ["", "Option1", 
            for row in range(0, self.model.rowCount(0)):
                self.table.openPersistentEditor(self.model.index(row, 0))
        def add_row2table(self):
            if self.applyFixCheckBox.isChecked():
                # have to actively close the persistent editor, otherwise when reopening
                # an editor it is drawn ontop of the old one
                for row in range(0, self.model.rowCount(0)):
                    self.table.closePersistentEditor(self.model.index(row, 0))
            index = sorted(self.table.selectionModel().selectedRows())
            if index != []:
                self.model.addRow(index[0].row(), ['Option1', '', '', '', ''])
            else: # add row at the end
                self.model.addRow(-1, ['Option1', '', '', '', ''])
        def delete_row_from_table(self):
            indexes = sorted(self.table.selectionModel().selectedRows())
            if indexes != []:
                if self.applyFixCheckBox.isChecked():
                    # have to actively close the persistent editor, otherwise when
                    # reopening an editor it is drawn ontop of the old one
                    for row in range(0, self.model.rowCount(0)):
                            self.model.index(row, 0))
                ind = [elem.row() for elem in indexes]
                for i in ind:
        def closeEvent(self,event):
    if __name__ == '__main__':   
        app = QApplication.instance()
        # prevent kernel crash at every second run of the program due to bug 
        # in iPython 
        if app is None:
            app = QApplication(sys.argv)
        main = Main()

  • Lifetime Qt Champion

    There's no need to close them first.

    The issue here comes rather from the replacement of the delegate. There's no need for that. If you just set it in the constructor and trigger the persistent editors when you add a line, you should be fine.

    One thing that might be worth checking is why replacing the delegate does not close de persistent editor. I do not know whether it's on purpose as you asked for a persistent editor after all.

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