#[repr(transparent)]pub struct Binding { /* private fields */ }Expand description
Binding is the representation of a binding between a property on a
Object instance (or source) and another property on another Object
instance (or target).
Whenever the source property changes, the same value is applied to the target property; for instance, the following binding:
⚠️ The following code is in C ⚠️
g_object_bind_property (object1, "property-a",
object2, "property-b",
G_BINDING_DEFAULT);
will cause the property named “property-b” of object2 to be updated
every time [ObjectExt::set()][crate::prelude::ObjectExt::set()] or the specific accessor changes the value of
the property “property-a” of object1.
It is possible to create a bidirectional binding between two properties
of two Object instances, so that if either property changes, the
other is updated as well, for instance:
⚠️ The following code is in C ⚠️
g_object_bind_property (object1, "property-a",
object2, "property-b",
G_BINDING_BIDIRECTIONAL);
will keep the two properties in sync.
It is also possible to set a custom transformation function (in both directions, in case of a bidirectional binding) to apply a custom transformation from the source value to the target value before applying it; for instance, the following binding:
⚠️ The following code is in C ⚠️
g_object_bind_property_full (adjustment1, "value",
adjustment2, "value",
G_BINDING_BIDIRECTIONAL,
celsius_to_fahrenheit,
fahrenheit_to_celsius,
NULL, NULL);
will keep the “value” property of the two adjustments in sync; the
celsius_to_fahrenheit function will be called whenever the “value”
property of adjustment1 changes and will transform the current value
of the property before applying it to the “value” property of adjustment2.
Vice versa, the fahrenheit_to_celsius function will be called whenever
the “value” property of adjustment2 changes, and will transform the
current value of the property before applying it to the “value” property
of adjustment1.
Note that Binding does not resolve cycles by itself; a cycle like
object1:propertyA -> object2:propertyB
object2:propertyB -> object3:propertyC
object3:propertyC -> object1:propertyA
might lead to an infinite loop. The loop, in this particular case,
can be avoided if the objects emit the signal::Object::notify signal only
if the value has effectively been changed. A binding is implemented
using the signal::Object::notify signal, so it is susceptible to all the
various ways of blocking a signal emission, like g_signal_stop_emission()
or g_signal_handler_block().
A binding will be severed, and the resources it allocates freed, whenever
either one of the Object instances it refers to are finalized, or when
the Binding instance loses its last reference.
Bindings for languages with garbage collection can use
unbind() to explicitly release a binding between the source
and target properties, instead of relying on the last reference on the
binding, source, and target instances to drop.
Binding is available since GObject 2.26
Implements
Implementations§
source§impl Binding
impl Binding
sourcepub fn flags(&self) -> BindingFlags
pub fn flags(&self) -> BindingFlags
Retrieves the flags passed when constructing the Binding.
Returns
the BindingFlags used by the Binding
sourcepub fn source_property(&self) -> GString
pub fn source_property(&self) -> GString
Retrieves the name of the property of property::Binding::source used as the source
of the binding.
Returns
the name of the source property
sourcepub fn target_property(&self) -> GString
pub fn target_property(&self) -> GString
Retrieves the name of the property of property::Binding::target used as the target
of the binding.
Returns
the name of the target property
sourcepub fn unbind(&self)
pub fn unbind(&self)
Explicitly releases the binding between the source and the target
property expressed by self.
This function will release the reference that is being held on
the self instance if the binding is still bound; if you want to hold on
to the Binding instance after calling unbind(), you will need
to hold a reference to it.
Note however that this function does not take ownership of self, it
only unrefs the reference that was initially created by
ObjectExt::bind_property() and is owned by the binding.
Trait Implementations§
source§impl Ord for Binding
impl Ord for Binding
source§impl<OT: ObjectType> PartialOrd<OT> for Binding
impl<OT: ObjectType> PartialOrd<OT> for Binding
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self and other) and is used by the <=
operator. Read moresource§impl StaticType for Binding
impl StaticType for Binding
source§fn static_type() -> Type
fn static_type() -> Type
Self.impl Eq for Binding
impl Send for Binding
impl Sync for Binding
Auto Trait Implementations§
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source§impl<T> Cast for Twhere
T: ObjectType,
impl<T> Cast for Twhere
T: ObjectType,
source§fn upcast<T: ObjectType>(self) -> Twhere
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V: ToValue,
source§fn set_property_from_value(&self, property_name: &str, value: &Value)
fn set_property_from_value(&self, property_name: &str, value: &Value)
source§fn set_properties(&self, property_values: &[(&str, &dyn ToValue)])
fn set_properties(&self, property_values: &[(&str, &dyn ToValue)])
source§fn set_properties_from_value(&self, property_values: &[(&str, Value)])
fn set_properties_from_value(&self, property_values: &[(&str, Value)])
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fn property_value(&self, property_name: &str) -> Value
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fn property_type(&self, property_name: &str) -> Option<Type>
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fn find_property(&self, property_name: &str) -> Option<ParamSpec>
ParamSpec of the property property_name of this object.source§fn list_properties(&self) -> PtrSlice<ParamSpec>
fn list_properties(&self) -> PtrSlice<ParamSpec>
ParamSpec of the properties of this object.source§fn freeze_notify(&self) -> PropertyNotificationFreezeGuard
fn freeze_notify(&self) -> PropertyNotificationFreezeGuard
source§unsafe fn set_qdata<QD>(&self, key: Quark, value: QD)where
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key. Read moresource§fn block_signal(&self, handler_id: &SignalHandlerId)
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source§fn unblock_signal(&self, handler_id: &SignalHandlerId)
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source§fn stop_signal_emission(&self, signal_id: SignalId, detail: Option<Quark>)
fn stop_signal_emission(&self, signal_id: SignalId, detail: Option<Quark>)
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&self,
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after: bool,
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) -> SignalHandlerIdwhere
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&self,
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&self,
signal_id: SignalId,
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callback: F
) -> SignalHandlerIdwhere
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&self,
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&self,
signal_id: SignalId,
details: Option<Quark>,
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callback: F
) -> SignalHandlerIdwhere
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&self,
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callback: F
) -> SignalHandlerIdwhere
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&self,
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after: bool,
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) -> SignalHandlerIdwhere
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&self,
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details: Option<Quark>,
after: bool,
callback: F
) -> SignalHandlerIdwhere
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&self,
signal_id: SignalId,
details: Option<Quark>,
after: bool,
callback: F
) -> SignalHandlerIdwhere
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&self,
signal_name: &str,
after: bool,
closure: RustClosure
) -> SignalHandlerId
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&self,
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after: bool,
closure: RustClosure
) -> SignalHandlerId
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&self,
signal_id: SignalId,
details: Option<Quark>,
after: bool,
closure: RustClosure
) -> SignalHandlerId
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signal_id: SignalId,
details: Option<Quark>,
after: bool,
closure: RustClosure
) -> SignalHandlerId
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&self,
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&self,
signal_name: &str,
args: &[Value]
) -> Option<Value>
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&self,
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details: Quark,
args: &[Value]
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&self,
signal_name: &str,
details: Quark,
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args: &[&dyn ToValue]
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&self,
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args: &[Value]
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&self,
signal_id: SignalId,
details: Quark,
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) -> Option<Value>
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&self,
name: Option<&str>,
f: F
) -> SignalHandlerIdwhere
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&self,
name: Option<&str>,
f: F
) -> SignalHandlerIdwhere
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source§fn bind_property<'f, 't, O, 'a>(
&'a self,
source_property: &'a str,
target: &'a O,
target_property: &'a str
) -> BindingBuilder<'a, 'f, 't>where
O: ObjectType,
fn bind_property<'f, 't, O, 'a>(
&'a self,
source_property: &'a str,
target: &'a O,
target_property: &'a str
) -> BindingBuilder<'a, 'f, 't>where
O: ObjectType,
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unsafe fn run_dispose(&self)
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impl<T> StaticTypeExt for Twhere
T: StaticType,
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fn ensure_type()
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fn to_send_value(&self) -> SendValue
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