CODEWITHSUNDEEP
qtlistviewpropertiesqml
jimav
jimav

Reputation: 860

Why can't ListView delegate refer to properties of ListView?

If a ListView contains user-defined properties, these properties can be referenced in a binding for model but they can not for anything inside the delegate. Why is this?

The docs seem to say that a Component should be able see properties in enclosing scopes where it was declared. 

import QtQuick 2.12
import QtQuick.Controls 2.12

ApplicationWindow {
    visible:true

    ListView {
        orientation: ListView.Vertical; height: 300; width: 100

        property var myCount: 3
        property var myMessage: "Hello"

        Component {
          id: myComp
          Text {text: myMessage} // ReferenceError: myMessage is not defined
        }
        model: myCount // this works
        delegate: myComp
    }       
}

(In my real application, the ListView is a component (.qml file) and the invoker needs to pass in information needed to configure the delegate; not literal text like in this example, but information for a nested ListView.)

Thanks for any help...

Upvotes: 1

Views: 367

Answers (1)

eyllanesc
eyllanesc

Reputation: 244301

The variables in QML have a scope, in your case when using myMessage without reference these indicating that the variable belongs to the Text item.

# ...
Component {
    id: myComp
    Text {text: myMessage} 
}
# ...

So the solution is to use the ListView id as a reference:

# ...
ListView {
    id: lv
    orientation: ListView.Vertical; height: 300; width: 100
    property var myCount: 3
    property var myMessage: "Hello"
    Component {
      id: myComp
      Text {text: lv.myMessage} 
    }
    model: myCount // this works
    delegate: myComp
}
# ...

Upvotes: 2

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