Access Modifiers in VB.net with Example – List of Access Modifiers

What is Access Modifiers in VB.net?

Access Modifiers in VB.net are the keywords, and those are useful to define an accessibility level for all the types and type members.

Access modifiers can control whether they can be accessed in other classes or current assembly or other assemblies based on your requirements.

List of Access Modifiers in VB.net

The keywords that specify access level are called access modifiers.

Public

The Public keyword in the declaration statement specifies that the element can be accessed from code anywhere in the same project, from other projects that reference the project, and from any assembly built from the project.

The following code shows a simple Public declaration of Access Modifiers in VB.net:

Public Class Customer
    Public Property Id As Integer
    Public Property Name As String
    Public Property Address As String

    Public Sub New()
    End Sub

    Public Sub New(ByVal id As Integer, ByVal name As String, ByVal address As String)
        Me.Id = id
        Me.Name = name
        Me.Address = address
    End Sub

    Public Sub Print()
        Console.WriteLine("Id: {0}, Name: {1}, Address: {2}", Me.Id, Me.Name, Me.Address)
    End Sub
End Class

• You can use Public only at module, interface, or namespace level.
• You can declare a public element at the level of a source file or namespace, or inside an interface, module, class, or structure, but not in a procedure.

Protected

The Protected keyword in the declaration statement specifies that the element can be accessed only from within the same class, or from a class derived from this class.

The following code shows a simple Protected declaration:

Public Class Customer
    Protected Property Id As Integer
    Protected Property Name As String
    Protected Property Address As String

    Public Sub New()
    End Sub

    Public Sub New(ByVal id As Integer, ByVal name As String, ByVal address As String)
        Me.Id = id
        Me.Name = name
        Me.Address = address
    End Sub

    Protected Sub Print()
        Console.WriteLine("Id: {0}, Name: {1}, Address: {2}", Me.Id, Me.Name, Me.Address)
    End Sub
End Class

In the above example, you can see that a Customer class is defined with the required variables and methods using the Protected access modifier.

• You can use Protected only at class level, and only when you declare a member of a class.
• You can declare a protected element in a class, but not at the level of a source file or namespace, or inside an interface, module, structure, or procedure.

Friend

The Friend keyword in the declaration statement specifies that the element can be accessed from within the same assembly, but not from outside the assembly.

The following code shows a simple Friend declaration.

Public Class Customer
    Friend Property Id As Integer
    Friend Property Name As String
    Friend Property Address As String

    Public Sub New()
    End Sub

    Public Sub New(ByVal id As Integer, ByVal name As String, ByVal address As String)
        Me.Id = id
        Me.Name = name
        Me.Address = address
    End Sub

    Friend Sub Print()
        Console.WriteLine("Id: {0}, Name: {1}, Address: {2}", Me.Id, Me.Name, Me.Address)
    End Sub
End Class

• You can use Friend only at the module, interface, or namespace level.
• You can declare a friend element at the level of a source file or namespace, or inside an interface, module, class, or structure, but not in a procedure.

Protected Friend

The Protected Friend keyword combination in the declaration statement specifies that the element can be accessed either from derived classes from within the same assembly, or both.

The following code shows a simple Protected Friend declaration.

Public Class Customer
    Protected Friend Property Id As Integer
    Protected Friend Property Name As String
    Protected Friend Property Address As String

    Public Sub New()
    End Sub

    Public Sub New(ByVal id As Integer, ByVal name As String, ByVal address As String)
        Me.Id = id
        Me.Name = name
        Me.Address = address
    End Sub

    Protected Friend Sub Print()
        Console.WriteLine("Id: {0}, Name: {1}, Address: {2}", Me.Id, Me.Name, Me.Address)
    End Sub
End Class

• You can use Protected Friend only at class level, and only when you declare a member of a class.
• You can declare a protected friend element in a class, but not at the level of a source file or namespace, or inside an interface, module, structure, or procedure.

Private

The Private keyword in the declaration statement specifies that the element can be accessed only from within the same module, class, or structure.

The following code shows a simple Private declaration.

Public Class Customer
    Private Property Id As Integer
    Private Property Name As String
    Private Property Address As String

    Public Sub New()
    End Sub

    Public Sub New(ByVal id As Integer, ByVal name As String, ByVal address As String)
        Me.Id = id
        Me.Name = name
        Me.Address = address
    End Sub

    Public Sub Print()
        Console.WriteLine("Id: {0}, Name: {1}, Address: {2}", Me.Id, Me.Name, Me.Address)
    End Sub
End Class

You can use Private only at the module level. IT means you can declare a private element inside a module, class, or structure, but not at the level of a source file or namespace, inside an interface, or in a procedure.

• At the module level, the Dim statement without any access level keywords is equivalent to a Private declaration.
• However, you might want to use the Private keyword to make your code easier to read and interpret.

Private Protected

The Private Protected keyword combination in the declaration statement specifies that the element can be accessed only from within the same class, as well as from derived classes found in the same assembly as the containing class.

The Private Protected access modifier is supported starting with Visual Basic 15.5.

The following example shows a Private Protected declaration.

Public Class Customer
    Private Protected Property Id As Integer
    Private Protected Property Name As String
    Private Protected Property Address As String

    Public Sub New()
    End Sub

    Public Sub New(ByVal id As Integer, ByVal name As String, ByVal address As String)
        Me.Id = id
        Me.Name = name
        Me.Address = address
    End Sub

    Public Sub Print()
        Console.WriteLine("Id: {0}, Name: {1}, Address: {2}", Me.Id, Me.Name, Me.Address)
    End Sub
End Class

• You can declare a Private Protected element only inside of a class.
• You cannot declare it within an interface or structure, nor can you declare it at the level of a source file or namespace, inside an interface or a structure, or in a procedure.

List of Available Modifiers in VB.net

The following table provides the complete list of VB.net modifiers.

Summary

One of the most confusing aspects of OOP is determining the proper access modifier to use for classes and class data members and methods.

If you provide too much scope for a data member or method, you risk violating data encapsulation, leading to unwanted data access.

If your scope is too restrictive, other classes that need access to a class’s data or methods won’t be able to access them.

In this chapter we discuss the different access modifiers, how they are used to manage class members and method scoping, and when to use each modifier.

At the end of the chapter, we discuss how these access modifiers work with the classes themselves.

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