Code Snippet: ViewModelBase

Oft benötige ich eine Implementierung der ViewModelBase-Klasse, dann muss ich diese entweder aus anderen Projekten kopieren, oder googeln. Jetzt muss ich das nicht mehr, denn ich merk sie mir einfach hier:

// parts of this code is based upon the article : http://msdn.microsoft.com/de-de/magazine/dd419663.aspx#id0090051
class ViewModelBase : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    /// <summary>
    /// raises the PropertyChanged event with the given string parameter
    /// </summary>
    /// <param name="propertyName">name of the property, that has changed</param>
    protected virtual void OnPropertyChanged(string propertyName)
    {
        // just to avoid wrong Event-Calls (only in debug mode)
        this.VerifyPropertyName(propertyName);

        // call the event handler
        PropertyChangedEventHandler handler = this.PropertyChanged;
        if (handler != null)
        {
            var e = new PropertyChangedEventArgs(propertyName);
            handler(this, e);
        }
    }

    /// <summary>
    /// raises the PropertyChanged-event, with the name of the property that is given by the lambda expression
    /// </summary>
    /// <typeparam name="Tprop">type parameter of the given property, to be ignored</typeparam>
    /// <param name="property">the lambda expression f.e.: "() => TestProperty"</param>
    protected virtual void OnPropertyChanged<Tprop>(Expression<Func<Tprop>> property)
    {
        // cast as LambdaExpression
        LambdaExpression lambda_exp = (LambdaExpression)property;
        if (lambda_exp != null) 
        {
            MemberExpression member_exp = (MemberExpression)lambda_exp.Body;
            if (member_exp != null)
            {
                OnPropertyChanged(member_exp.Member.Name);
                return;
            }
        }
        Debug.Fail("No correct LambdaExpression provided for OnPropertyChanged.");
    }

    [Conditional("DEBUG")]
    [DebuggerStepThrough]
    public void VerifyPropertyName(string propertyName)
    {
        // Verify that the property name matches a real,  
        // public, instance property on this object.
        if (TypeDescriptor.GetProperties(this)[propertyName] == null)
        {
            string msg = "Invalid property name: " + propertyName;
            Debug.Fail(msg);
        }
    }
}