In Visual Basic .NET, a field is a member of a class that holds data or a reference to an object. Fields can be declared at the class level, outside any method or property, and have a specific data type. Here's an example of how to declare and use fields in a class:
Public Class Student
Public Name As String
Private Age As Integer
Public Sub New(name As String, age As Integer)
Me.Name = name
Me.Age = age
End Sub
Public Sub GetAge()
Console.WriteLine("{0}'s age is {1}", Me.Name, Me.Age)
End Sub
End Class
In this example, we have a Student class with two fields: Name and Age. Name is declared as a Public field, meaning its value can be accessed by any code that has a reference to a Student object. Age is declared as a Private field, meaning only code within the Student class can access it.
The Sub New method is a constructor that initializes the Name and Age fields when a new Student object is created. We use the Me keyword to refer to the object being created.
The GetAge method is a public method that displays the name and age of the student. It can access both the Name and Age fields.
We can create a new Student object and set its Name and Age fields like this:
Dim s As New Student("John", 18)
s.Name = "Jane"
We can then call the GetAge method to display the student's age:
s.GetAge()
This would output "Jane's age is 18" to the console.