Working with PropertyEnumeration in Python

[sliptonic]

I'm typically add an enum property to a FeaturePython object and initialize its value like this:

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obj.addProperty("App::PropertyEnumeration", "myproperty")
obj.myproperty = ['first', 'second', 'third']
obj.myproperty = 'third'

But I have a case where I can't populate the enumeration until after the proxy is set. So when I populate it and then set it, the onChanged event is called twice. How can I detect if this onchanged event is firing because the enum is getting populated rather than the value actually changing?

I tried looking at the property's value, but in the first call it is equal to the first item in the list.

[Paula]

We often get these sorts of issues in web application development. The best method I have found is to remove the GUI widget's onChange() callback, set the data then add back the onChange() callback.

[onekk]

Another way could be a "freeze" of the automagics.

In some interface, there is a way to say "stop to reacting" to something, and then "restore the normal behaviour".

In this way when dealing with complex things, you can "freeze" the object modify all the things, some operations could affect the "automagic" so some things could became broken during modifications, once done the modification you should restart the normal behaviour and update the thing.

Now I don't know if simply adding such methods (stop and ) could be viable or simple, like I have seen recently some similar methods in PathJobGui.py

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   FreeCAD.ActiveDocument.openTransaction(translate("Path_Job", "Create Job"))

   FreeCAD.ActiveDocument.commitTransaction()

   FreeCAD.ActiveDocument.abortTransaction()

Simply as an example.

Regards

Carlo D.

[Chris_G]

Hi,

How can I detect if this onchanged event is firing because the enum is getting populated rather than the value actually changing?

Maybe you can store the actual enumeration in the proxy instance and check if it has changed in onChanged() :

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class myProxy:
    def __init__(self, obj):
        self.prop_enumeration = ["a", "b", "c"]
        obj.addProperty("App::PropertyEnumeration", "myProp").myProp = self.prop_enumeration

    def onChanged(self, obj, prop):
        if prop == "myProp":
            if not obj.getEnumerationsOfProperty("myProp") == self.prop_enumeration:
                self.prop_enumeration = obj.getEnumerationsOfProperty("myProp")
                print("myProp : enumeration has changed")
            else:
                print("myProp : value has changed")