src/Tizen.NUI/src/internal/XamlBinding/Interactivity/EventTrigger.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.Linq;
   4 using System.Reflection;
   5 using Tizen.NUI.Binding.Internals;
   6
   7 namespace Tizen.NUI.Binding
   8 {
   9     [ContentProperty("Actions")]
  10     internal sealed class EventTrigger : TriggerBase
  11     {
  12         static readonly MethodInfo s_handlerinfo = typeof(EventTrigger).GetRuntimeMethods().Single(mi => mi.Name == "OnEventTriggered" && mi.IsPublic == false);
  13         readonly List<BindableObject> _associatedObjects = new List<BindableObject>();
  14
  15         EventInfo _eventinfo;
  16
  17         string _eventname;
  18         Delegate _handlerdelegate;
  19
  20         public EventTrigger() : base(typeof(BindableObject))
  21         {
  22             Actions = new SealedList<TriggerAction>();
  23         }
  24
  25         public IList<TriggerAction> Actions { get; }
  26
  27         public string Event
  28         {
  29             get { return _eventname; }
  30             set
  31             {
  32                 if (_eventname == value)
  33                     return;
  34                 if (IsSealed)
  35                     throw new InvalidOperationException("Event cannot be changed once the Trigger has been applied");
  36                 OnPropertyChanging();
  37                 _eventname = value;
  38                 OnPropertyChanged();
  39             }
  40         }
  41
  42         internal override void OnAttachedTo(BindableObject bindable)
  43         {
  44             base.OnAttachedTo(bindable);
  45             if (!string.IsNullOrEmpty(Event))
  46                 AttachHandlerTo(bindable);
  47             _associatedObjects.Add(bindable);
  48         }
  49
  50         internal override void OnDetachingFrom(BindableObject bindable)
  51         {
  52             _associatedObjects.Remove(bindable);
  53             DetachHandlerFrom(bindable);
  54             base.OnDetachingFrom(bindable);
  55         }
  56
  57         internal override void OnSeal()
  58         {
  59             base.OnSeal();
  60             ((SealedList<TriggerAction>)Actions).IsReadOnly = true;
  61         }
  62
  63         void AttachHandlerTo(BindableObject bindable)
  64         {
  65             try
  66             {
  67                 _eventinfo = bindable.GetType().GetRuntimeEvent(Event);
  68                 _handlerdelegate = s_handlerinfo.CreateDelegate(_eventinfo?.EventHandlerType, this);
  69             }
  70             catch (Exception)
  71             {
  72                 Console.WriteLine("EventTrigger", "Can not attach EventTrigger to {0}.{1}. Check if the handler exists and if the signature is right.", bindable.GetType(), Event);
  73             }
  74             if (_eventinfo != null && _handlerdelegate != null)
  75                 _eventinfo.AddEventHandler(bindable, _handlerdelegate);
  76         }
  77
  78         void DetachHandlerFrom(BindableObject bindable)
  79         {
  80             if (_eventinfo != null && _handlerdelegate != null)
  81                 _eventinfo.RemoveEventHandler(bindable, _handlerdelegate);
  82         }
  83
  84         // [Preserve]
  85         void OnEventTriggered(object sender, EventArgs e)
  86         {
  87             var bindable = (BindableObject)sender;
  88             foreach (TriggerAction action in Actions)
  89                 action.DoInvoke(bindable);
  90         }
  91     }
  92 }