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(
        [CallerMemberNamestring propertyName = )
    {
        PropertyChanged?.Invoke(thisnew 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 { getset; }
    public string Password { getset; }
}

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.

One thought on “INotifyPropertyChange without boilerplate code in Xamarin.Forms

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s