Constants in VB.NET

Definition: Constant is a memory location to store data / value. It store one value at a time.

Property: The main property of a constant is that the value stored in it donot changes throughout the program execution.

Declaring Constants:

Const statement is used to declare and allocate memory for one or more variables.  The syntax of declaring variable using Const statement is

[{ Public | Protected | Friend | Protected Friend | Private }]  [Shadows] Const constantname [As datatype] [= expression | initialvalue]

~ Parts of Const Statement ~

• Public: The constant declared as Public means that you can access data anywhere without any restrictions.

• Protected: Suppose a constant is declare inside the class and you do not want it to be access outside the class then protected access specifier allows you to declare a constant that is only accessible in the class where it is declared and its derived class. 
• Protected Friend:
• Private: Private access specifier allows you to declare a constant that is only accesible in the class where it is declared. You cannot access the Private constant outside the class.
• Shadows: 
• constantname: A user defined name of a constant. Multiple constant names must be separated by commas. 
• datatype: Specifies the type of data stored in a constant. If you do not specify the datatype, the constant takes the datatype of expression | initialvalue.  If you do not specify datatype and expression, the datatype is set to Object. 
• expression | initialvalue: Used to initialize a constant. in case of expression , the result is assigned as inital value.