How to know if a PropertyInfo is a collection

Below is some code I use to get the initial state of all public properties in a class for IsDirty checking.

What's the easiest way to see if a property is IEnumerable?

Cheers,
Berryl

  protected virtual Dictionary<string, object> _GetPropertyValues()
    {
        return _getPublicPropertiesWithSetters()
            .ToDictionary(pi => pi.Name, pi => pi.GetValue(this, null));
    }

    private IEnumerable<PropertyInfo> _getPublicPropertiesWithSetters()
    {
        return GetType().GetProperties().Where(pi => pi.CanWrite);
    }

UPDATE

What I wound up doing was adding a few library extensions as follows

    public static bool IsNonStringEnumerable(this PropertyInfo pi) {
        return pi != null && pi.PropertyType.IsNonStringEnumerable();
    }

    public static bool IsNonStringEnumerable(this object instance) {
        return instance != null && instance.GetType().IsNonStringEnumerable();
    }

    public static bool IsNonStringEnumerable(this Type type) {
        if (type == null || type == typeof(string))
            return false;
        return typeof(IEnumerable).IsAssignableFrom(type);
    }

if (typeof(IEnumerable).IsAssignableFrom(prop.PropertyType) && prop.PropertyType != typeof(string))

I agree with Fyodor Soikin but the fact that is Enumerable does not mean that is only a Collection since string is also Enumerable and returns the characters one by one...

So i suggest using

if (typeof(ICollection<>).IsAssignableFrom(pi.PropertyType))

Try

private bool IsEnumerable(PropertyInfo pi)
{
   return pi.PropertyType.IsSubclassOf(typeof(IEnumerable));
}