<div dir="ltr">I just did a test, it seems that the behavior is slightly different from PyQt4, which fires the signal only once.<div><br></div><div>According to <a href="https://bugreports.qt.io/browse/QTBUG-30672">https://bugreports.qt.io/browse/QTBUG-30672</a> it's the intended behavior:<br></div><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">dataChanged() is emitted immediately when a new change is cached and also when the record is refreshed from the database table after submitting. A connected view needs to know about both. The record's values after refreshing are not necessarily the same as the values in the cache before submitting.</blockquote><div><br></div><div>According to my tests, the signal is indeed emitted the first time when the data is actually changed, while the second time the signal is emitted even if no actual data has actually changed, with the first and last column of the affected row as arguments of the slot, as the data is actually submitted (as in commit) to the database.<br></div><div><div><br></div><div>This can be demonstrated as also related to the EditStrategy of the QSqlTableModel: when the strategy is set to OnManualSubmit, the signal is emitted only the first time.<br>As expected, using QSqlTableModel.revertAll() obviously fires the signal with the reverted data.</div><div>Strangely enough (I can try and understand why, but it still seems a bit inconsistent), after manually calling submitAll() with this strategy, dataChanged is not emitted.</div></div><div><br></div><div>If you don't want this "duplicate" behaviour, I can see three possibilities:</div><div>1. Add topLeft/bottomRight arguments to the slot method and ignore changes applied to topLeft != bottomRight. In simple case scenarios, this shouldn't be a problem, as 99% of dataChange are usually related to a single index (meaning that topLeft and bottomRight arguments are the same). You could eventually be thorough by checking indexes' row() and column() properties.<br>2. Change the strategy to OnManualSubmit and manually submitAll() data in the onDataChanged slot. I wouldn't suggest this one.<br>3. Subclass QSqlTableModel with a custom signal, implement setData() and manually emit the custom signal when role == QtCore.Qt.EditRole. In this case, it might be better to ensure that the data is actually submitted before sending the signal:<br></div><div><br></div><div><font face="monospace, monospace">class SubClassModel(QtSql.QSqlTableModel):<br></font></div><div><div><font face="monospace, monospace"> myDataChanged = QtCore.Signal(QtCore.QModelIndex, object)<br></font></div><div><font face="monospace, monospace"><br></font></div><div><font face="monospace, monospace"> def setData(self, index, value, role=QtCore.Qt.EditRole):</font></div><div><font face="monospace, monospace"> if role == QtCore.Qt.EditRole:</font></div><div><font face="monospace, monospace"> result = QtSql.QSqlTableModel.setData(self, index, value, role)</font></div><div><font face="monospace, monospace"> if result:</font></div><div><font face="monospace, monospace"> self.myDataChanged.emit(index, value)</font></div><div><font face="monospace, monospace"> return result</font></div><div><font face="monospace, monospace"> return QtSql.QSqlTableModel.setData(self, index, value, role)</font><br></div></div><div><br></div><div><br></div><div>Maurizio</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">2018-08-11 11:34 GMT+02:00 J Barchan <span dir="ltr"><<a href="mailto:jnbarchan@gmail.com" target="_blank">jnbarchan@gmail.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_default" style="font-family:tahoma,sans-serif"></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On 11 August 2018 at 05:31, Zhao Lee <span dir="ltr"><<a href="mailto:redstone-cold@163.com" target="_blank">redstone-cold@163.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-left-style:solid"><div><div class="h5"><div><div style="color:rgb(0,0,0);font-family:arial;font-size:14px">The sample code as following </div><div style="color:rgb(0,0,0);font-family:arial;font-size:14px"><br></div><div><span style="background-color:rgb(255,255,255)">self.tableView.setModel(self.s<wbr>qlTableModel)</span></div><div><span style="background-color:rgb(255,255,255)">self.sqlTableModel.dataChanged<wbr>.connect(self.onDataChanged)</span></div><div><br></div><div><div><span style="background-color:rgb(255,255,255)">@pyqtSlot(QModelIndex, QModelIndex) # ,QVector:name 'QVector' is not defined</span></div><div><span style="background-color:rgb(255,255,255)"> def onDataChanged(self):</span></div><div><span style="background-color:rgb(255,255,255)"> print('onDataChanged--------')</span></div></div><div style="color:rgb(0,0,0);font-family:arial;font-size:14px"><br></div><div style="color:rgb(0,0,0);font-family:arial;font-size:14px">each time when I edit a cell in the table view, the QAbstractItemModel::dataCh<wbr>anged() was triggered two times , I guess my decorator for QAbstractItemModel::dataChange<wbr>d() may be wrong , so what's the right decorator for it ?</div><div style="color:rgb(0,0,0);font-family:arial;font-size:14px"><br></div><div style="color:rgb(0,0,0);font-family:arial;font-size:14px"><br></div><div style="color:rgb(0,0,0);font-family:arial;font-size:14px"><br></div></div><br><br><span title="neteasefooter"><p> </p></span><br></div></div>______________________________<wbr>_________________<br>
PyQt mailing list <a href="mailto:PyQt@riverbankcomputing.com" target="_blank">PyQt@riverbankcomputing.com</a><br>
<a href="https://www.riverbankcomputing.com/mailman/listinfo/pyqt" rel="noreferrer" target="_blank">https://www.riverbankcomputing<wbr>.com/mailman/listinfo/pyqt</a><br></blockquote></div><br><div class="gmail_default" style="font-family:tahoma,sans-serif">I'm a PyQt user but not an expert. Whether your decorator is right or wrong I cannot see it would make any difference to how often a slot is called. I presume it's called twice for some other reason.</div><span class="HOEnZb"><font color="#888888"><br clear="all"><br>-- <br><div class="m_1058783516155111231gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><span style="font-family:tahoma,sans-serif">Kindest,</span></div><div><span style="font-family:tahoma,sans-serif">Jonathan</span></div></div></div></div></div>
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