•  Abstraction 

1. Abstraction is "To represent the essential feature without representing the background details."
2. Abstraction lets you focus on what the object does instead of how it does it.
   
3. Abstraction provides you a generalized view of your classes or objects by providing relevant information
   
4. Abstraction is the process of hiding the working style of an object, and showing the information of an object in an understandable manner.

• Encapsulation 
1. Hiding the internal state and functionality of an objec...

• check abstract equality i.e. it does the necessary type conversions before doing the equality comparison
  

• Its a way to achieve abstraction in c#.
• Not instantiated directly
• must contain at least one abstract method.
• used to define base class.
• contains both declaration and definition.
• contains constructor.
• it can contain static members
• contains different types of access modifiers like public, private, protected.
• performance of abstract class is fast.
• used to implement core identity of class
• a class can only use one abstract class.
• if many implementation are same kind and common behavior, then it...

Token-based authentication is a protocol which allows users to verify their identity, and in return receive a unique access token. During the life of the token, users then access the website or app that the token has been issued for, rather than having to re-enter credentials each time they go back to the same webpage, app, or any resource protected with that same token.

Auth tokens work like a stamped ticket. The user retains access as long as the token remains valid. Once the user logs out o...

You can solve the issue by adding below lines in web.config file.

 <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral"/>
        <bindingRedirect oldVersion="0.0.0.0-8.0.0.0" newVersion="8.0.0.0"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>