Required property not working with repeater

Question

I have a component like this:

import QtQuick 2.15 Item { id: root property double value: 0.0 property int core: 1 property color progressBarColor: "black" property color minMaxTextColor: "black" property int fontSize: height - 6 //.... }

Now I thought it would be a good idea to make some propertis required since they are should be declared when the component is used. So I changed to this:

import QtQuick 2.15 Item { id: root required property double value required property int core property color progressBarColor: "black" property color minMaxTextColor: "black" property int fontSize: height - 6 //.... }

The Component gets called in a repeater likes this:

SystemInformation{ id: sysinfo } Column{ id: displayColumn Repeater{ model: sysinfo.coreUtilizationsInPercent.length CoreUtilizationDisplay{ width: root.elementWidth height: root.elementHeight fontSize: root.fontSize progressBarColor: "#3399FF" // blue minMaxTextColor: "blue" core: index + 1 value: sysinfo.coreUtilizationsInPercent[index] } } }

Now this works fine until I make the properties required. I wonder why It does not work?

If I declare it required I get this error:

qrc:/qml/SystemInformationDisplay.qml:57: ReferenceError: index is not defined

I did the same with similar components which are not in the repeater and there it works fine.

Why?

Why delegate? All the other functionality was working without it. — Sandro4912
– Sandro4912, Commented Jun 20, 2020 at 13:10
Even with adding delegate there still comes the error as soon as I declare the properties required — Sandro4912
– Sandro4912, Commented Jun 20, 2020 at 14:39
@Sandro4912 I think it's a bug, report it. The delegate is irrelevant since in the case of Repeater the delegate is a default-property — eyllanesc
– eyllanesc, Commented Jun 21, 2020 at 22:11

SebastianH · Accepted Answer · 2020-08-12 13:32:06Z

From the qt develop blog

And if your delegates do not contain required properties, nothing changes here. However, if they contain at least one required property, those names are not accessible anymore. Instead, you have to explicitly opt in by specifying them as required properties.

In this case you need to add the requiered property index to the component.

import QtQuick 2.15 Item { id: root required property double value required property int core required property int index // add it property color progressBarColor: "black" property color minMaxTextColor: "black" property int fontSize: height - 6 //.... }

With this additional index you can build your component and have access to index. You do not need to specify index. This is done, since it is a delegate.

Repeater{ model: sysinfo.coreUtilizationsInPercent.length delegate: CoreUtilizationDisplay{ width: root.elementWidth height: root.elementHeight fontSize: root.fontSize progressBarColor: "#3399FF" // blue minMaxTextColor: "blue" core: index + 1 value: sysinfo.coreUtilizationsInPercent[index] } }

More informations can be found in the documentation

thanks for the late answer. I would have never guessed that you have to add the index explicitly
Today I run in the same problem. I think the behavior is not intuitive.
I wasted 3 hours on this thing. Qt should definitely throw a bug in cases like this.
Qt Documentation : Note: model, index, and modelData roles are not accessible if the delegate contains required properties, unless it has also required properties with matching names.

Collectives™ on Stack Overflow

Required property not working with repeater

1 Answer 1

4 Comments

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Related