C# - What is the Difference between Const and Readonly

Const:

•       Const can only be initialized at the time of declaration of the field.
•       Const values will evaluate at compile time only.
•      Const value can’t be changed these will be same at all the time.
•      This type of fields are required when one of the field values remains constant throughout the system like Pi will remain same in your Maths Class.

Read-only:

•     The value will be initialized either declaration time or the constructor of the class allowing you to pass the value at run time.
•     Read only values will evaluate at runtime only.