ObservableObjectBase Class

Provides a base class for component model classes, which can notify their consumer about property changes.

Definition

Namespace: KGySoft.ComponentModel
Assembly: KGySoft.CoreLibraries (in KGySoft.CoreLibraries.dll) Version: 7.0.0-rc.1
C#
[SerializableAttribute]
public abstract class ObservableObjectBase : INotifyPropertyChanged, 
	IDisposable, ICloneable
Inheritance
Object    ObservableObjectBase
Derived
Implements
INotifyPropertyChanged, ICloneable, IDisposable

Remarks

Implementers can use the Get and Set methods in the property accessors to manage event raising automatically.

Consumers can subscribe the PropertyChanged event to get notification about the property changes.

Accessing properties can be fine tuned by overriding the CanGetProperty and CanSetProperty methods. By default they allow accessing the instance properties in the implementer class.

Example

The following example shows a possible implementation of a derived class.
C#
public class MyModel : ObservableObjectBase
{
    // A simple integer property (with zero default value). Until the property is set no value is stored internally.
    public int IntProperty { get => Get<int>(); set => Set(value); }

    // An int property with a specified default value. Until the property is set the default will be returned.
    public int IntPropertyCustomDefault { get => Get(-1); set => Set(value); }

    // If the default value is a complex one, which should not be evaluated each time you can provide a factory for it:
    // When this property is read for the first time without setting it before, the provided delegate will be invoked
    // and the returned default value is stored without triggering the PropertyChanged event.
    public MyComplexType ComplexProperty { get => Get(() => new MyComplexType()); set => Set(value); }

    // You can use regular properties to prevent raising the events and not to store the value in the internal storage.
    // The OnPropertyChanged method still can be called explicitly to raise the PropertyChanged event.
    public int UntrackedProperty { get; set; }
}

Constructors

ObservableObjectBase Initializes a new instance of the ObservableObjectBase class.

Properties

IsDisposed Gets whether this instance has already been disposed.
IsModified Gets whether this instance has been modified. Modified state can be set by the SetModified method.
MissingProperty Represents the value of a missing property value. Can be returned in PropertyChangedExtendedEventArgs by the PropertyChanged event if the stored value of the property has just been created and had no previous value, or when a property has been removed from the inner storage.

Methods

AffectsModifiedState Gets whether the change of the specified propertyName affects the IsModified property.
The ObservableObjectBase implementation excludes the IsModified property itself.
CanGetProperty Gets whether the specified property can be retrieved.
The base implementation allows to get the actual instance properties in this instance.
CanSetProperty Gets whether the specified property can be set.
The base implementation allows to set the actual instance properties in this instance if the specified value is compatible with the property type.
Clone Creates a new object that is a copy of the current instance.
The base implementation clones the internal property storage, the IsModified property and if clonePropertyChanged is , then also the subscribers of the PropertyChanged event.
Dispose Releases the resources held by this instance.
Dispose(Boolean) Releases the resources held by this instance.
The base implementation removes the subscribers of the PropertyChanged event and clears the property storage. If the overridden method disposes properties accessed by the Get<T> and Set methods, then check the IsDisposed property first and call the base method as the last step to prevent ObjectDisposedException.
GetT(FuncT, String) Gets the value of a property, or - if it was not set before -, then creates its initial value. The created initial value will be stored in the internal property storage without triggering the PropertyChanged event. For constant or simple expressions, or to return a default value for a non-existing property without storing it internally use the other Get overload.
For an example, see the Remarks section of the ObservableObjectBase class.
GetT(T, String) Gets the value of a property or defaultValue if no value is stored for it. No new value will be stored if the property does not exist. If the default initial value is too complex and should not be evaluated every time when the property is get, or to throw an exception for an uninitialized property use the other Get overload.
For an example, see the Remarks section of the ObservableObjectBase class.
OnPropertyChanged Raises the PropertyChanged event.
ResetProperty Resets the property of the specified name, meaning, it will be removed from the underlying storage so the getter methods will return the default value again.
ResumeChangedEvent Resumes the raising of the PropertyChanged event suspended by the SuspendChangeEvents method.
Set Sets the value of a property.
For an example, see the Remarks section of the ObservableObjectBase class.
SetModified Sets the modified state of this ObservableObjectBase instance represented by the IsModified property.
SuspendChangedEvent Suspends the raising of the PropertyChanged event until ResumeChangeEvents method is called. Supports nested calls.

Events

PropertyChanged Occurs when a property value changed. The actual type of the event argument is PropertyChangedExtendedEventArgs.

Extension Methods

Convert Converts an Object specified in the obj parameter to the desired targetType.
See the Examples section of the generic ConvertTTarget(Object, CultureInfo) overload for an example.
(Defined by ObjectExtensions)
ConvertTTarget Converts an Object specified in the obj parameter to the desired TTarget.
(Defined by ObjectExtensions)
CreatePropertyBinding Creates a special binding for the PropertyChanged event of the specified source, which allows to update the specified targetPropertyName in the targets, when the property of sourcePropertyName changes in the source.
(Defined by Command)
CreatePropertyBinding Creates a special binding for the PropertyChanged event of the specified source, which allows to update the specified targetPropertyName in the targets, when the property of sourcePropertyName changes in the source.
(Defined by Command)
CreatePropertyChangedHandlerBinding Creates a special command binding for the PropertyChanged event of the specified source that invokes the specified handler only when the changed property is among the specified propertyNames.
(Defined by Command)
CreatePropertyChangedHandlerBinding Creates a special command binding for the PropertyChanged event of the specified source that invokes the specified handler only when the changed property is among the specified propertyNames.
(Defined by Command)
CreateSynchronizedPropertyBinding Creates a special binding for the PropertyChanged event of the specified source, which allows to update the specified targetPropertyName in the targets, when the property of sourcePropertyName changes in the source. The target properties will be set using the SynchronizationContext of the thread on which this method was called.
(Defined by Command)
CreateSynchronizedPropertyBinding Creates a special binding for the PropertyChanged event of the specified source, which allows to update the specified targetPropertyName in the targets, when the property of sourcePropertyName changes in the source. The target properties will be set using the SynchronizationContext of the thread on which this method was called.
(Defined by Command)
CreateTwoWayPropertyBinding Creates a pair of special bindings for the PropertyChanged event of the specified source and target, which allow to update the specified targetPropertyName and sourcePropertyName in both directions when any of them changes.
(Defined by Command)
In Gets whether item is among the elements of set.
See the Examples section of the generic InT(T, T) overload for an example.
(Defined by ObjectExtensions)
TryConvert Tries to convert an Object specified in the obj parameter to the desired targetType.
See the Examples section of the ConvertTTarget(Object, CultureInfo) method for a related example.
(Defined by ObjectExtensions)
TryConvert Tries to convert an Object specified in the obj parameter to the desired targetType.
See the Examples section of the ConvertTTarget(Object, CultureInfo) method for a related example.
(Defined by ObjectExtensions)
TryConvertTTarget Tries to convert an Object specified in the obj parameter to the desired TTarget.
See the Examples section of the ConvertTTarget(Object, CultureInfo) method for a related example.
(Defined by ObjectExtensions)
TryConvertTTarget Tries to convert an Object specified in the obj parameter to the desired TTarget.
See the Examples section of the ConvertTTarget(Object, CultureInfo) method for a related example.
(Defined by ObjectExtensions)

Thread Safety

Static members of this type are safe for multi-threaded operations. Instance members of this type are safe for multi-threaded operations.

See Also