This repository contains relevant abstractions and implementations for one- and two-way binding of properties, for notifications about changed properties, for notifications about changed collections and for the Relay Command Pattern for synchronous and asynchronous operations.
Depending on the application, there are several ways to skin a cat.
Designed with one or two way binding in mind.
public INotifiableProperty<int> NotifiableInt { get; set; } = new NotifiableProperty<int>(default);
If the property is changed, the PropertyChangingEventHandler
is triggered before the value changes and the PropertyChangedEventHandler
is triggered after the value has changed.
- The
PropertyChangingEventHandler
contains via thePropertyChangingEventArgs
the name of the property that is changing and when casted toPropertyChangingEventArgs<T>
the old value of the property. - The
PropertyChangedEventHandler
contains via thePropertyChangedEventArgs
the name of the property that has changed and when casted toPropertyChangedEventArgs<T>
the new value of the property.
Further implementation possibilities can be achieved with the help of the INotifiableProperty<T>
interface.
Designed to handle changes at the class level and propagate them.
public sealed class TestClass : NotifiableObject
{
private int _property;
public int Property
{
get => _property;
set => SetProperty(ref _property, value);
}
}
If the property is changed, the PropertyChangingEventHandler
is triggered before the value changes and the PropertyChangedEventHandler
is triggered after the value has changed.
- The
PropertyChangingEventHandler
contains via thePropertyChangingEventArgs
the name of the property that is changing and when casted toPropertyChangingEventArgs<T>
the old value of the property. - The
PropertyChangedEventHandler
contains via thePropertyChangedEventArgs
the name of the property that has changed and when casted toPropertyChangedEventArgs<T>
the new value of the property.
Further implementation possibilities can be achieved with the help of the INotifiableObject
interface.
The NotifiableCollection
class provides methods to handle the change within a collection and propagate it to the outside.
public sealed class MyStringCollection : NotifiableCollection, ICollection<string>
{
private readonly Collection<string> _collection;
public MyStringCollection()
=> _collection = new Collection<string>();
..
}
Most of the implementation must be done despite the base class itself. The intention has been to be able to signal the state of a collection before (CollectionChangingEventHandler
) or after (CollectionChangedEventHandler
) the addition, deletion or modification of objects.
- The
CollectionChangingEventHandler
contains via theCollectionChangingEventArgs
theCollectionChangeAction
and when casted toCollectionChangingEventArgs<T>
the old value of the object. - The
CollectionChangedEventHandler
contains via theCollectionChangedEventArgs
theCollectionChangeAction
and when casted toCollectionChangedEventArgs<T>
the new value of the object.
Further implementation possibilities can be achieved with the INotifiableCollection
interface or the INotifyCollectionChanged
and INotifyCollectionChanging
interfaces.
The NotifyChangedAttribute
and the NotifyChangingAttribute
propagating the information also to those properties the are defined via the constructor. An example implementation could look like this:
private sealed class TestClass : NotifyPropertyBase
{
private int _quantity;
private int _value;
public TestClass(int quantity, int value)
{
Quantity = quantity;
Value = value;
}
[NotifyChanged(nameof(TotalValue))]
public int Quantity { get => _quantity; set => SetProperty(ref _quantity, value); }
[NotifyChanged(nameof(TotalValue))]
public int Value { get => _value; set => SetProperty(ref _value, value); }
public int TotalValue => Quantity * Value;
}
If the Quantity
property or the Value
property is changed, a PropertyChanged
event is also triggered for the TotalValue
property.
The complete API documentation can be found here.