using System; using System.ComponentModel; namespace Xamarin.Forms { public abstract class Effect { internal Effect() { } public Element Element { get; internal set; } public bool IsAttached { get; private set; } public string ResolveId { get; internal set; } #region Statics public static Effect Resolve(string name) { Type effectType; Effect result = null; if (Registrar.Effects.TryGetValue(name, out effectType)) { result = (Effect)Activator.CreateInstance(effectType); } if (result == null) result = new NullEffect(); result.ResolveId = name; return result; } #endregion // Received after Control/Container/Element made valid protected abstract void OnAttached(); // Received after Control/Container made invalid protected abstract void OnDetached(); internal virtual void ClearEffect() { if (IsAttached) SendDetached(); Element = null; } internal virtual void SendAttached() { if (IsAttached) return; OnAttached(); IsAttached = true; } internal virtual void SendDetached() { if (!IsAttached) return; OnDetached(); IsAttached = false; } internal virtual void SendOnElementPropertyChanged(PropertyChangedEventArgs args) { } } }