When to use ':' versus '='?
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I'm learning QML. I'm playing with an application that uses a ListView, and I'm using a delegate. In all of this QML, properties are set using a ':'.
I wanted to know how to do something when a delegate was tapped, and I found some code that does it. But in that code is the line
list_view1.currentIndex = indexMy question is why in this case is '=' used instead of ':'? And more generally, when is each appropriate? I can't seem to find this in the documentation.
Thanks.
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Hi,
Because it's assigning index to currentIndex, it's not setting its property.
:is used when you set the properties when declaring the object. For the rest of the code, you can't do that. -
I'm learning QML. I'm playing with an application that uses a ListView, and I'm using a delegate. In all of this QML, properties are set using a ':'.
I wanted to know how to do something when a delegate was tapped, and I found some code that does it. But in that code is the line
list_view1.currentIndex = indexMy question is why in this case is '=' used instead of ':'? And more generally, when is each appropriate? I can't seem to find this in the documentation.
Thanks.
Hi,
@treaves said:
My question is why in this case is '=' used instead of ':'?
Because that is JavaScript code, and JavaScript only lets you assign values using '='.
And more generally, when is each appropriate?
':' has a few different uses in QML. In your case, ':' performs a property binding. In contrast, '=' performs an assignment.
See http://doc.qt.io/qt-5/qtqml-syntax-propertybinding.html for an explanation of property bindings.
