SitefinityUserControl example

protected override CacheLevel ControlCacheLevel {
    get {
        return CacheLevel.ContentListener;
    }
}

protected override List<CacheDependencyKey> GetCacheDependencyObjects() {
    var cacheDependencyObjects = new List<CacheDependencyKey>();

    //Example listening to any PageNode event - e.g., a Navigation control
    cacheDependencyObjects.Add(new CacheDependencyKey() {
        Type = typeof(PageNode),
        Key = null
    });

    //Example listening to any NewsItem event - e.g., a News List type control
    cacheDependencyObjects.Add(new CacheDependencyKey() {
        Type = typeof(NewsItem),
        Key = null
    });

    //Example listening to a single Image Item - e.g., a banner control or similar...
    //NOTE: in a real example, you would use a public Guid as the key, and use that same Guid to get/display the image
    //    : The .ToUpperInvariant() is important
    cacheDependencyObjects.Add(new CacheDependencyKey() {
        Type = typeof(Telerik.Sitefinity.Libraries.Model.Image),
        Key = "A72D2064-DB9A-6D2B-9FAD-FF0000A141DD".ToUpperInvariant()
    });

    //If this is a Control that has Comments available, you'll want to listen to all Comment events
    //That way, when a new one is added, the page this control lives on will automatically invalidate
    cacheDependencyObjects.Add(new CacheDependencyKey() {
        Type = typeof(Comment),
        Key = null
    });

    return cacheDependencyObjects;
}