INPC Weaver example

AfterWeaving.cs

public class SomeViewModel : INotifyPropertyChanged
{
    private string <URL>k__BackingField;

    public event PropertyChangedEventHandler PropertyChanged;

    public string URL
    {
        [CompilerGenerated]
        get
        {
            return this.<URL>k__BackingField;
        }
        [CompilerGenerated]
        set
        {
            if (string.Equals(this.<URL>k__BackingField, value, StringComparison.Ordinal))
            {
                return;
            }
            this.<URL>k__BackingField = value;
            this.OnPropertyChanged("HostName");
            this.OnPropertyChanged("URL");
        }
    }

    public string HostName
    {
        get
        {
            string result;
            try
            {
                Uri typedURL = new Uri(this.URL);
                result = typedURL.Host;
            }
            catch (UriFormatException)
            {
                result = "";
            }
            return result;
        }
    }

    public virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler propertyChanged = this.PropertyChanged;
        if (propertyChanged != null)
        {
            propertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

BeforeWeaving.cs

public class SomeViewModel : INotifyPropertyChanged
{
    public string URL { get; set; }

    public string HostName
    {
        get
        {
            try
            {
                var typedURL = new Uri(URL);
                return typedURL.Host;
            }
            catch (UriFormatException)
            {
                return "";
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
}