How Does Event Handling Work in C#?

In -depth understanding of the event processing in C#

Incident detailed explanation

In the user interface, the incident represents a move to respond to the user input or other system events. The event statement is as follows:

Event processing procedure and its importance

<code class="language-c#">public void EventName(object sender, EventArgs e);</code>

Event processing procedure is a method executed during the event. They are essential for response events and execute the required operation, for example:

Update the user interface according to the change of the data source

Navigation to the new page in the web application

In response to the user's operation to save data
• Create event processing procedures
To create an event processing program, you must:

Define a signature (return type and parameter) to the method to be executed.

Create an event using the commission as a signature.

Implement the processing procedure that conforms to the entrusted signature.

• Subscribe the event processing program to the event.
Example
• Consider the following example:

In this example:

MyEventhandler entrusts the method to return VOID and accepts string parameters.

Somethinghappending Event uses MyEventhandler as its signature, allowing it to call the event processing program that conforms to the signature.

<code class="language-c#">// 委托
public delegate void MyEventHandler(string foo);

// 事件
public event MyEventHandler SomethingHappened;

// 事件处理程序
void HandleSomethingHappened(string foo)
{
    // 当 SomethingHappened 触发时执行的代码
}

// 订阅事件处理程序
myObj.SomethingHappened += new MyEventHandler(HandleSomethingHappened);

// 触发事件
SomethingHappened("bar");</code>

Handlesomythinghappened method was created as an event processing program.

Event processing program has been subscribed to the Somethinghappending event, which means that when it is somedHAPPENED trigger, handlesomethinghaputhappend will be called.
When the SomethingHappened event is triggered, the handlesomyominghaputHappened will be executed and the parameter value passed to the event.

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