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<p>Hi Marian,</p>
<p>Just tell Qt that it shouldn't create the connection more than
once using Qt::UniqueConnection.</p>
<p>Cheers</p>
<p>Matthias<br>
</p>
<br>
<div class="moz-cite-prefix">On 10/2/17 5:30 PM, Tudorache, Marian
wrote:<br>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi everyone,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have connected the signal
selectionChanged so some code, which is executed after
features are selected.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">myLayer.selectionChanged.connect(self.executeAfterSelection)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Then I have a method self.
executeAfterSelection(self, featuresIds)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The SIGNAl/SLOT tandem works but now I
realized every time when I call
<b>myLayer.selectionChanged.connect(self.executeAfterSelection)</b>
It does not overwrite my previous call. It creates a second
signa/slot tandem. During running the method
executeAfterSelection is excuted twice, three times etc.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">How can I check if the SIGNAL
selectionChanged is connected to the slot
executeAfterSelection before I run
myLayer.selectionChanged.connect(self.executeAfterSelection)?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I tried this:<o:p></o:p></p>
<p class="MsoNormal">receiversCount =
QtCore.QObject.receivers(QtCore.SIGNAL(“selectionChanged()”)<o:p></o:p></p>
<p class="MsoNormal">receiversCount =
QtCore.QObject.receivers(QtCore.SIGNAL(“selectionChanged”)<o:p></o:p></p>
<p class="MsoNormal">receiversCount =
QtCore.QObject.receivers(QtCore.SIGNAL(“myLayer.selectionChanged()”)<o:p></o:p></p>
<p class="MsoNormal">receiversCount =
QtCore.QObject.receivers(QtCore.SIGNAL(“myLayer.selectionChanged”)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Every time I get this error:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">QObject.receivers(SIGNAL()): first argument
of unbound method must have type ‘QObject’).<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Marian<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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