Detailed explanation of how C# implements a secure event subscriber

1. Explain what event subscriber is

In the context of C#, an event subscriber is a mechanism for handling specific events.

Event: Event is something that happens in a software application, such as buttons being clicked, data being changed, etc. In C#, events are defined by delegate declared using the event keyword. DevExpress controls and frameworks often trigger various events so that your application can respond to user interactions or other system changes.

Event Subscriber: An event subscriber is an object that subscribes to (or listens to) an event and performs corresponding actions when an event occurs.

2. What is the function of event subscriber

Notify the subscription object, inform the change of occurrence, and notify the data when the change occurs to the specific subscription delegation method.

3. Sample code

I encapsulate a global event subscriber here, using a static function method to implement global calls, and try to store the currently subscribed message with a field to prevent the problem of multiple subscriptions for an event.

The code is as follows:

 public static class EventSubscriber
 {
     /// &lt;summary&gt;
     /// Subscribe to the message dictionary     /// &lt;/summary&gt;
     private static Dictionary&lt;string, SendMessageHandler&gt; MsgDict = new Dictionary&lt;string, SendMessageHandler&gt;();
     public delegate void SendMessageHandler(object MsgContent);

     /// &lt;summary&gt;
     /// Subscribe to message     /// &lt;/summary&gt;
     /// <param name="name">Message unique name</param>     /// <param name="AcceptFunction">Methods to accept messages</param>     /// &lt;exception cref="Exception"&gt;&lt;/exception&gt;
     public static void SubMsg(string name, SendMessageHandler AcceptFunction)
     {
         if (!(name))
         {
             (name, AcceptFunction);
         }
         else
         {
             // throw new Exception("already" + name + "name subscription");         }
     }

     /// &lt;summary&gt;
     /// Remove the specified subscription message     /// &lt;/summary&gt;
     /// <param name="name">Message name</param>     public static void UnSubMsg(string name)
     {
         if ((name))
         {
             (name);
         }
     }

     /// &lt;summary&gt;
     /// Send a message     /// &lt;/summary&gt;
     /// <param name="name">Message name</param>     /// <param name="msgContent">Message content</param>     public static void SendMsg(string name, object msgContent)
     {
         if ((name))
         {
             MsgDict[name].Invoke(msgContent);
         }
     }
 }

How to use:

Subscribe to message:

  ("GetDataTable", SendMessageHandler);

When the message is notified, the data passed by the event is obtained and processed

    public void SendMessageHandler(object MsgContent)
    {
        var data = (DataTable?)MsgContent;
        TableWait = true;
    }

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