Dynamic invocation implementation method for events in C #

The example in this article describes how C # dynamically invokes events. In general, the traditional idea is to obtain information about the event through Reflection.eventinfo, then use the Getraisemethod method to get the method called after the event is triggered, and then use Methodinfo.invoke to invoke the event's dynamic invocation.

Unfortunately, the Reflection.EventInfo.GetRaiseMethod method always returns NULL. This is because the C # compiler does not generate metadata information about Raisemethod at all when compiling and processing the events defined by the event keyword, so getraisemethod cannot get the event-triggered processing at all. Thottam R. Sriram briefly introduces this issue in its using Setraisemethod and Getraisemethod and invoking the method dynamically, and through reflection . Emit related methods to generate Raisemethod manually, and finally use regular Getraisemethod to implement event-triggered method calls. This is a very complicated practice.

The following code is a simple workaround that also enables dynamic invocation of events. The specific code is as follows:

Public event eventhandler<eventargs> myeventtobefired;public void FireEvent (Guid instanceId, string handler) {  //Note:this is being fired from a method with in the same class that defined the event (i.e. "this").  EventArgs e = new EventArgs (instanceId);  MulticastDelegate eventdelagate = (multicastdelegate) this   . GetType ()   . GetField (Handler, BindingFlags.Instance | BindingFlags.NonPublic)   . GetValue (this);  Delegate[] delegates = Eventdelagate.getinvocationlist ();  foreach (Delegate dlg in delegates)  {    dlg. Method.invoke (dlg. Target, new object[] {this, e});}  } FireEvent (New Guid (), "myeventtobefired");

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Dynamic invocation implementation method for events in C #

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Dynamic invocation implementation method for events in C #