Understand the proxy and events in C # (2)

Understand the proxy and events in C # (2)

Hey! Hello, do you remember the on behalf of the agent? Do you want to ask me to write?

The reason is very simple they say that there are more than 7 or more, it can be a special writer. Oh, God, in fact this is my ninth article

But that two. It is still in the review. In fact, the structure, the agent and the incident are connected, but it is

Separate two topics discussed. This is why I want to separate, because many friends use the proxy and events at first

When it is used to add an event to a Button or a form. So you can often see, there is

One person will naturally think of the time driver of Windows. Yes is the most commonly used, but in fact

It is also possible to use separate, at least the agent is that. The agent can leave the event independently survive. The one above

As you can see. Ok, let me say, let us enter the topic.

event:

Understand incident, this is not difficult, in fact, everyone is experiencing such or such incidents every day, then consisting, you

Life. Think about it, a weather forecaster informs you to say tomorrow. It is natural, you will think of it, you should take an umbrella. Yes

This is the event. Weather forecast issues this event notification, then you will handle this event. What you do is to bring your umbrella to rain.

Just like you often do it, you click on a Button and issue a Click event, which is of course handling this incident, perhaps

Popping a window, or something else can happen, or even shut down the computer. These are user events. Because users

Trigger the GUI and then these events.

Let's take a look at how it is handled in C #. Then I mentioned in front of the article, turning the verbs into nouns. What would you think?

Is it ing? Haha .. Opening a joke, of course, we are not in English. Well, it is a proxy, just like you often do.

In the IDE environment, you drag a button to the form, then double-click it, what do you see? Do you enter the code interface? Then you will

To handle events. But what is the relationship between this and the agent? Well, why don't you find it carefully?

This.button1.click = new system.eventhandler (this.button1_click); a sentence in your initializeComponent () function. Yes, this is the agent. It puts the event in the agent. So what?

In this.Button1_Click method, you will see it has two parameters, one is the object type Sender, this is simple

As the name suggests it is the initiator of the event. Who is it, you just ask it. So the second? Is it an event, right?

Of course, the initiator is coming with his incident, just like the weather forecast with his weather forecast. Ok, I believe in me.

Humans have a day to make weather. Listening to me, I have to make a long-term weather, etc.

We will always create new weather effects, how is it? Hehe .. It is a good idea, although it is

A joke. Ok, you will say that I am going crazy, why don't you say this? No, I want to talk about a new topic. That is user-defined

Events and system predefined events. Then let's discuss these two events separately.

User-defined event:

I believe that the code will always be most convincing. Just like you don't want to see the textbook, I will be more willing to see the science and teacher movie.

The following code is the fact that I want to explain.

Using system.drawing; using system.componentmodel; using system.windows.form; using system.data ;. using system.data ;. USING SYSTEM.DATA;

A summary description of Namespace useevent {///