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Property-var: Difference between revisions
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==QtQuick 1.x== | == QtQuick 1.x == | ||
* There was no javascript var type property, but property variant, internally a QVariant. | * There was no javascript var type property, but property variant, internally a QVariant. | ||
* Assigning a JavaScript object to that property would result in it being converted to a QVariantMap. | * Assigning a JavaScript object to that property would result in it being converted to a QVariantMap. | ||
* Accessing that property from JS would result in that QVariantMap being converted back into a JS object. | * Accessing that property from JS would result in that QVariantMap being converted back into a JS object. | ||
* JS function reference, special JS values (null, undefined) could not be stored in the | * JS function reference, special JS values (null, undefined) could not be stored in the 'property variant' type of property. | ||
==QtQuick 2.0== | == QtQuick 2.0 == | ||
* Deprecated | * Deprecated "property variant" and added "property var; internally they are javascript values. | ||
* Support storing of anything created in JS, including JS function references. | * Support storing of anything created in JS, including JS function references. | ||
* Only when accessed from C++ (via QObject::property() or QQmlProperty::read()) will be converted to a QVariant (same conversions rules of any other JS value to QVariant conversion apply). | * Only when accessed from C++ (via QObject::property() or QQmlProperty::read()) will be converted to a QVariant (same conversions rules of any other JS value to QVariant conversion apply). | ||
* When implementing types on the C++ side, one can use the | * When implementing types on the C++ side, one can use the QJSValue class as a property/method parameter to transfer values between C++ and QML/JS without type/data loss. | ||
** Includes JS functions; for example, you can assign a function to a property from | ** Includes JS functions; for example, you can assign a function to a property from QML and call it later from C++ using QJSValue::call(). | ||
Latest revision as of 21:46, 28 June 2015
QtQuick 1.x
- There was no javascript var type property, but property variant, internally a QVariant.
- Assigning a JavaScript object to that property would result in it being converted to a QVariantMap.
- Accessing that property from JS would result in that QVariantMap being converted back into a JS object.
- JS function reference, special JS values (null, undefined) could not be stored in the 'property variant' type of property.
QtQuick 2.0
- Deprecated "property variant" and added "property var; internally they are javascript values.
- Support storing of anything created in JS, including JS function references.
- Only when accessed from C++ (via QObject::property() or QQmlProperty::read()) will be converted to a QVariant (same conversions rules of any other JS value to QVariant conversion apply).
- When implementing types on the C++ side, one can use the QJSValue class as a property/method parameter to transfer values between C++ and QML/JS without type/data loss.
- Includes JS functions; for example, you can assign a function to a property from QML and call it later from C++ using QJSValue::call().