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Diffstat (limited to 'src/imports/controls/doc/src')
-rw-r--r-- | src/imports/controls/doc/src/qtquickcontrols2-qmltypes.qdoc | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/src/imports/controls/doc/src/qtquickcontrols2-qmltypes.qdoc b/src/imports/controls/doc/src/qtquickcontrols2-qmltypes.qdoc index 7fbc8c4d..211abedc 100644 --- a/src/imports/controls/doc/src/qtquickcontrols2-qmltypes.qdoc +++ b/src/imports/controls/doc/src/qtquickcontrols2-qmltypes.qdoc @@ -48,6 +48,78 @@ \generatelist {qmltypesbymodule QtQuick.Controls} \noautolist + \section1 Using Qt Quick Controls types in property declarations + + As mentioned in \l {Qt Quick Templates 2 QML Types}, each type in Qt Quick + Controls is backed by a C++ "template" type. These types are \l {Qt Quick + Templates 2}{non-visual implementations of controls' logic and behavior}. + + For example, the \l Menu type's API and behavior is defined by the C++ + type in Qt Quick Templates. Each \l {Definition of a Style}{style} that + wants to provide a Menu must have a Menu.qml available, and the root + item in that file must be the Menu from Qt Quick Templates. When you + import QtQuick.Controls and create a Menu in QML, the type you get is + actually the QML Menu defined by the style's Menu.qml. + + In order to use a control as the type in a property declaration, you should + use the corresponding type from Qt Quick Templates. For example, suppose + you had a \c PopupOpener component, which was a Button that opened a + Popup: + + \qml + // PopupButton.qml + import QtQuick.Controls + + Button { + required property Popup popup + + onClicked: popup.open() + } + + // main.qml + PopupButton { + popup: saveChangesDialog + } + + Dialog { + id: saveChangesDialog + + // ... + } + \endqml + + Running this code will result in an error: + + \badcode + Unable to assign Dialog_QMLTYPE to Popup_QMLTYPE + \endcode + + This is because of the inheritance hierarchy: + + \badcode + Popup (C++ type in QtQuick.Templates) + │ └── Popup (QML type in QtQuick.Controls) + └── Dialog (C++ type in QtQuick.Templates) + └── Dialog (QML type in QtQuick.Controls) + \endcode + + Dialog from \c QtQuick.Controls does not derive from the Popup from + \c QtQuick.Controls, but from \c QtQuick.Templates. + + Instead, use the Popup from Qt Quick Templates as the property type: + + \qml + // PopupButton.qml + import QtQuick.Controls + import QtQuick.Templates as T + + Button { + required property T.Popup popup + + onClicked: popup.open() + } + \endqml + For more information on the Qt Quick Controls module, see the \l {Qt Quick Controls} module documentation. |