•  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...

• 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...

static readonly Regex re = new Regex(@"\$(\w+)\$", RegexOptions.Compiled);
static void Main() {
    string input = @"Dear $name$, as of $date$ your balance is $amount$";

    var args = new Dictionary<string, string>(
        StringComparer.OrdinalIgnoreCase) {
            {"name", "Mr Smith"},
            {"date", "05 Aug 2009"},
            {"amount", ...

We can use DateTime.Now.Ticks and Guid.NewGuid().ToString() to combine together and make a unique id.

As the DateTime.Now.Ticks is added, we can find out the Date and Time in seconds at which the unique id is created.

Please see the code.

var ticks = DateTime.Now.Ticks;
var guid = Guid.NewGuid().ToString();
var uniqueSessionId = ticks.ToString() +'-'+ guid; //guid created by combining ticks and guid

var datetime = new DateTime(ticks);//for checking purpose
var datetimenow = DateTime.Now;    //b...

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>