GitHub - thomaslevesque/EssentialMVVM: Minimalist MVVM framework (original) (raw)

A minimalist MVVM framework, which contains the basic building blocks I was tired of rewriting in each of my projects. It doesn't do much, but strives to do it well.

It targets .NET Framework 4.5, .NET Standard 1.3 and .NET Standard 2.0, so it should be usable on most XAML platforms.

Features

BindableBase

A class that implements INotifyPropertyChanged and can be used as a base class for ViewModels. It exposes two methods:

• OnPropertyChanged: raises the PropertyChanged event for the specified property name (if the name is not specified, it's inferred for the calling member).
• Set: assigns the specified value to the backing field of a property, if different from the current value, and raises PropertyChanged for that property. Can be chained to perform other actions if the value has changed. For instance:
  private string _foo;
  public string Foo
  {
  get => _foo;
  set => Set(ref _foo, value)
  .AndNotifyPropertyChanged(nameof(PropertyThatDependOnFoo))
  .AndRaiseCanExecuteChanged(_barCommand)
  .AndExecute(() => DoSomething())

}
public string PropertyThatDependsOnFoo => Foo?.ToUpper();
private DelegateCommand _barCommand;
public ICommand BarCommand => _barCommand ??= new DelegateCommand(Bar);
private void Bar() { }
private void DoSomething() { }
It can also be used in a condition, like this:
private string _foo;
public string Foo
{
get => _foo;
set
{
if (Set(ref _foo, value))
{
// Do something if the value changed
}
}
}

DelegateCommand and related classes

An implementation of ICommand that accepts a delegate to specify what the command does. Exists in multiple flavors:

• DelegateCommand: a synchronous command that takes no parameter.
• DelegateCommand<T>: a synchronous command that takes a parameter of type T.
• AsyncDelegateCommand: an asynchronous command that takes no parameter.
• AsyncDelegateCommand<T>: an asynchronous command that takes a parameter of type T.

An asynchronous command will not allow execution (i.e. CanExecute will return false) if the previous execution is incomplete.