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This article mainly introduces the use of VB.NET events in practical application, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, let the editor take you to understand it.

The constructor of the class in VB.NET is

Sub New ()

End sub

Of course, you can also add parameters. For example, the constructor of the Human class:

Sub New (Byval Name as string

Byval Gender as String, byval

Stature as integer)

Me.Name = Name'me is in VB.NET

Keyword, which represents the object itself, as in java

Me.Gender = this of Gender'.

Super in java is MyBase in VB.NET.

Me.Stature = Stature

End sub

In this way, our Lao Wang

Dim LaoWang As new Human

(Lao Wang, male, 177)

In this case, the Human object must be constructed with parameters. We can add an additional New procedure with no parameters. I skipped it here.

The object is not dead, but alive. The object should be able to actively make some representations to the outside world. This is the event. For example, a person gets sick. At this time, we will take him to the hospital. Let's first define a VB.NET event in the Human class:

Public event FallIll

Let's assume that someone eats too much and gets sick. Write in the Eat process:

Public sub Eat ()

Raiseevent FallIll

'The raiseevent is used to raise an event

End sub

How will the outside world receive this event? Use AddHandler. We need to define a process in sub Main first:

Sub GoToHospital

Console.WriteLine

The patient was taken to the hospital.

End sub

Then bind the process to an event of a specific object:

AddHandler LaoWang.FallIll

AddressOf GoToHospital

In this way, once the LaoWang.Eat is executed, the FallIll event is raised and the GoToHospital procedure is executed. The complete code for the VB.NET event is as follows:

Imports System public module MyModule

Sub Main 'does not call GoToHospital directly in sub Main.

Dim LaoWang as Human

LaoWang = new Human (Lao Wang, male, 177)

AddHandler LaoWang.FallIll

AddressOf GoToHospital

Console.writeline ("{0}, {1})

Height {2} cm ", _

LaoWang.Name, LaoWang.Gender

LaoWang.Stature)

LaoWang.Eat () 'event is raised here

Console.Read

End sub

Sub GoToHospital

Console.WriteLine ("the patient was taken to the hospital.")

End sub

End module

Public class Human

Public Name as String

Public Gender as String

Public Stature as integer

Sub New (Byval Name as string, byval

Gender as String, byval Stature as integer)

Me.Name = Name

Me.Gender = Gender

Me.Stature = Stature

End sub

Sub New () 'constructor with no arguments

End sub

Public event FallIll

Public sub Eat ()

Raiseevent FallIll

End sub

Public sub Sleep ()

End sub

Public sub SeeADoctor ()

End sub

Public function Born () as Human

If Gender = "female" then

Return new Human (",", 50)

Else

Return nothing

End if

End function

End class

VB.NET events can also take parameters. In this way, an event-related object can be attached when the event is raised, so that the catcher of the event can deal with it.

For example, let's change the definition of FallIll to:

Public event FallIll

(Byval Name as String)

Then change the content of Eat to:

Raiseevent FallIll (me.Name)

Give the name of the patient to the captor of the event.

Then change the definition of GoToHospital to:

Sub GoToHospital (Byval Name

As String)

'The number and type of parameters of the process must be captured with

The parameters of the event are the same

Console.WriteLine (Name &

"was taken to the hospital.")

End sub

At this time, we will see: "Lao Wang has been taken to the hospital."

Thank you for reading this article carefully. I hope the article "what is the use of VB.NET events in practical applications" shared by the editor will be helpful to everyone? at the same time, I also hope that you will support and pay attention to the industry information channel, and more related knowledge is waiting for you to learn!

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