2 // System.Reflection/EventInfo.cs
5 // Paolo Molaro (lupus@ximian.com)
7 // (C) 2001 Ximian, Inc. http://www.ximian.com
8 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
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30 using System.Diagnostics;
31 using System.Runtime.InteropServices;
33 namespace System.Reflection {
36 [ComDefaultInterfaceAttribute (typeof (_EventInfo))]
38 [ClassInterface(ClassInterfaceType.None)]
39 [StructLayout (LayoutKind.Sequential)]
40 public abstract class EventInfo : MemberInfo, _EventInfo {
41 AddEventAdapter cached_add_event;
43 public abstract EventAttributes Attributes {get;}
49 Type EventHandlerType {
52 MethodInfo add = GetAddMethod (true);
53 p = add.GetParametersInternal ();
55 Type t = p [0].ParameterType;
56 /* is it alwasys the first arg?
57 if (!t.IsSubclassOf (typeof (System.Delegate)))
58 throw new Exception ("no delegate in event");*/
70 bool IsMulticast {get {return true;}}
71 public bool IsSpecialName {get {return (Attributes & EventAttributes.SpecialName ) != 0;}}
72 public override MemberTypes MemberType {
73 get {return MemberTypes.Event;}
76 protected EventInfo() {
86 void AddEventHandler (object target, Delegate handler)
88 // this optimization cause problems with full AOT
89 // see bug https://bugzilla.xamarin.com/show_bug.cgi?id=3682
91 MethodInfo add = GetAddMethod ();
93 throw new InvalidOperationException ("Cannot add a handler to an event that doesn't have a visible add method");
94 if (target == null && !add.IsStatic)
95 throw new TargetException ("Cannot add a handler to a non static event with a null target");
96 add.Invoke (target, new object [] {handler});
98 if (cached_add_event == null) {
99 MethodInfo add = GetAddMethod ();
101 throw new InvalidOperationException ("Cannot add a handler to an event that doesn't have a visible add method");
102 if (add.DeclaringType.IsValueType) {
103 if (target == null && !add.IsStatic)
104 throw new TargetException ("Cannot add a handler to a non static event with a null target");
105 add.Invoke (target, new object [] {handler});
108 cached_add_event = CreateAddEventDelegate (add);
110 //if (target == null && is_instance)
111 // throw new TargetException ("Cannot add a handler to a non static event with a null target");
112 cached_add_event (target, handler);
116 public MethodInfo GetAddMethod() {
117 return GetAddMethod (false);
119 public abstract MethodInfo GetAddMethod(bool nonPublic);
120 public MethodInfo GetRaiseMethod() {
121 return GetRaiseMethod (false);
123 public abstract MethodInfo GetRaiseMethod( bool nonPublic);
124 public MethodInfo GetRemoveMethod() {
125 return GetRemoveMethod (false);
127 public abstract MethodInfo GetRemoveMethod( bool nonPublic);
129 public virtual MethodInfo[] GetOtherMethods (bool nonPublic) {
130 // implemented by the derived class
131 return EmptyArray<MethodInfo>.Value;
134 public MethodInfo[] GetOtherMethods () {
135 return GetOtherMethods (false);
139 [DebuggerStepThrough]
144 void RemoveEventHandler (object target, Delegate handler)
146 MethodInfo remove = GetRemoveMethod ();
148 throw new InvalidOperationException ("Cannot remove a handler to an event that doesn't have a visible remove method");
150 remove.Invoke (target, new object [] {handler});
154 public override bool Equals (object obj)
156 return obj == (object) this;
159 public override int GetHashCode ()
161 return base.GetHashCode ();
164 public static bool operator == (EventInfo left, EventInfo right)
166 if ((object)left == (object)right)
168 if ((object)left == null ^ (object)right == null)
170 return left.Equals (right);
173 public static bool operator != (EventInfo left, EventInfo right)
175 if ((object)left == (object)right)
177 if ((object)left == null ^ (object)right == null)
179 return !left.Equals (right);
183 void _EventInfo.GetIDsOfNames ([In] ref Guid riid, IntPtr rgszNames, uint cNames, uint lcid, IntPtr rgDispId)
185 throw new NotImplementedException ();
188 Type _EventInfo.GetType ()
190 // Required or object::GetType becomes virtual final
191 return base.GetType ();
194 void _EventInfo.GetTypeInfo (uint iTInfo, uint lcid, IntPtr ppTInfo)
196 throw new NotImplementedException ();
199 void _EventInfo.GetTypeInfoCount (out uint pcTInfo)
201 throw new NotImplementedException ();
204 void _EventInfo.Invoke (uint dispIdMember, [In] ref Guid riid, uint lcid, short wFlags, IntPtr pDispParams, IntPtr pVarResult, IntPtr pExcepInfo, IntPtr puArgErr)
206 throw new NotImplementedException ();
209 delegate void AddEventAdapter (object _this, Delegate dele);
211 // this optimization cause problems with full AOT
212 // see bug https://bugzilla.xamarin.com/show_bug.cgi?id=3682
213 // do not revove the above delegate or it's field since it's required by the runtime!
214 #if !FULL_AOT_RUNTIME
215 delegate void AddEvent<T, D> (T _this, D dele);
216 delegate void StaticAddEvent<D> (D dele);
218 #pragma warning disable 169
219 // Used via reflection
220 static void AddEventFrame<T,D> (AddEvent<T,D> addEvent, object obj, object dele)
223 throw new TargetException ("Cannot add a handler to a non static event with a null target");
225 throw new TargetException ("Object doesn't match target");
226 addEvent ((T)obj, (D)dele);
229 static void StaticAddEventAdapterFrame<D> (StaticAddEvent<D> addEvent, object obj, object dele)
233 #pragma warning restore 169
236 * The idea behing this optimization is to use a pair of delegates to simulate the same effect of doing a reflection call.
237 * The first delegate performs casting and boxing, the second dispatch to the add_... method.
239 static AddEventAdapter CreateAddEventDelegate (MethodInfo method)
243 object addHandlerDelegate;
244 MethodInfo adapterFrame;
245 Type addHandlerDelegateType;
248 if (method.IsStatic) {
249 typeVector = new Type[] { method.GetParametersInternal () [0].ParameterType };
250 addHandlerDelegateType = typeof (StaticAddEvent<>);
251 frameName = "StaticAddEventAdapterFrame";
253 typeVector = new Type[] { method.DeclaringType, method.GetParametersInternal () [0].ParameterType };
254 addHandlerDelegateType = typeof (AddEvent<,>);
255 frameName = "AddEventFrame";
258 addHandlerType = addHandlerDelegateType.MakeGenericType (typeVector);
260 // with Silverlight a coreclr failure (e.g. Transparent caller creating a delegate on a Critical method)
261 // would normally throw an ArgumentException, so we set throwOnBindFailure to false and check for a null
262 // delegate that we can transform into a MethodAccessException
263 addHandlerDelegate = Delegate.CreateDelegate (addHandlerType, method, false);
264 if (addHandlerDelegate == null)
265 throw new MethodAccessException ();
267 addHandlerDelegate = Delegate.CreateDelegate (addHandlerType, method);
269 adapterFrame = typeof (EventInfo).GetMethod (frameName, BindingFlags.Static | BindingFlags.NonPublic);
270 adapterFrame = adapterFrame.MakeGenericMethod (typeVector);
271 return (AddEventAdapter)Delegate.CreateDelegate (typeof (AddEventAdapter), addHandlerDelegate, adapterFrame, true);