INotifyPropertyChange without boilerplate code in Xamarin.Forms

Implementing INotifyPropertyChange is pretty straightforward. Usually, you create a base ViewModel class which implements it and which usually contains RaisePropertyChanged method:

public abstract class BaseViewModel : INotifyPropertyChanged
{
    #region INotifyPropertyChanged
    public event PropertyChangedEventHandler PropertyChanged;
    protected void RaisePropertyChanged(
        [CallerMemberName] string propertyName = "")
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
    #endregion
}

Now you can extend the BaseViewModel and use it this way:

public class UserViewModel : BaseViewModel
{

    private string login;

    public string Login

    {

        get

        {

            return login;

        }

        set

        {

            if (login == value)

                return;

            login = value;

            RaisePropertyChanged();

        }

    }

    private string password;

    public string Password

    {

        get

        {

            return password;

        }

        set

        {

            if (password == value)

                return;

            password = value;

            RaisePropertyChanged();

        }

    }

}

For very small applications it can be a good enough approach, however, in bigger applications it turns into a lot of boring boilerplate code. Here is where NotifyPropertyChanged.Fody comes into play! With this nice package our code will turn into:

[ImplementPropertyChanged]

public abstract class BaseViewModel {}

public class UserViewModel : BaseViewModel

{

    public string Login { get; set; }

    public string Password { get; set; }

}

Easy as it is! I highly recommend to get familiar with the documentation as it contains a lot of useful information about more advanced flows. For example, if you need to RaisePropertyChange for dependent properties or to skip equality comparison.