You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
65 lines
3.0 KiB
65 lines
3.0 KiB
/*!
|
|
@class QtMvvm::Binding
|
|
|
|
This class is returned by the bind() function as a handle to a binding. It can be used to check
|
|
if the binding is valid and can remove a binding again.
|
|
|
|
@note You don't need to keep the Binding as reference. The binding will stay even if you don't
|
|
hold any references to it. This class serves as a passive watcher over a binding.
|
|
|
|
@sa QtMvvm::bind
|
|
*/
|
|
|
|
/*!
|
|
@fn QtMvvm::Binding::isValid
|
|
|
|
@returns `true` If the binding is valid and active, `false` if invalid or already unbound
|
|
|
|
A binding is considered valid is if has successfully been set up and has not been unbound yet.
|
|
A valid binding means view and viewModel are valid can the properties could be found.
|
|
|
|
@sa Binding::unbind, bind()
|
|
*/
|
|
|
|
/*!
|
|
@fn QtMvvm::bind(QObject*, const char*, QObject*, const char*, Binding::BindingDirection, const char*, const char*)
|
|
|
|
@param viewModel The object in the role of a viewmodel
|
|
@param viewModelProperty The property of the viewmodel to use in the binding
|
|
@param view The object in the role of a view
|
|
@param viewProperty The property of the view to use in the binding
|
|
@param type The type/direction of binding to create
|
|
@param viewModelChangeSignal An alternative signal to be used instead of the viewModelProperty
|
|
notify signal to detect property changes
|
|
@param viewChangeSignal An alternative signal to be used instead of the viewProperty notify
|
|
signal to detect property changes
|
|
@returns A handle to the newly created binding, or an invalid handle on errors
|
|
|
|
The methods creates a binding similar to the QML bindings, but it is possible to create two-way
|
|
bindings with this method as well. A binding means that whenever a property changes, the property
|
|
it is bound to is updated to the changed value as well.
|
|
|
|
@code{.cpp}
|
|
//sample usage
|
|
QtMvvm::bind(this->viewModel, "name", // A viewmodel that has a property named "name"
|
|
ui->nameLabel, "text"); // A view (for example a QLabel) that has a property named "text"
|
|
//any changes to "name" will update "text" and the other way around
|
|
@endcode
|
|
|
|
To control the directions, i.e. which properties should trigger an update on changes and which
|
|
only get updated, use the `type` parameter.
|
|
|
|
@attention Unlike the QML variant, this binding **does not handle binding loops**. THis means if
|
|
you use a two way binding, make shure change signals are only emitted when the value does actually
|
|
change. Otherwise your application is caught up in a binding loop and will eventually crash. Using
|
|
two seperate one way bindings will not prevent this.
|
|
|
|
If the properties you want to use don't have a change signal or you don't want to use that signal,
|
|
you can use the `viewModelChangeSignal` and `viewChangeSignal` to overwrite the signal to be used.
|
|
Please note that you must specify the full signal signature. For example, the signatur of the
|
|
signal `void foo(const QString &bar);` has the signature `foo(QString)`. See QMetaMethod for more
|
|
details. If you leave the parameter out or set it to `nullptr` (or `{}`, an invalid meta method)
|
|
the notify signals of the properties are used.
|
|
|
|
@sa Binding
|
|
*/
|
|
|