A constant pattern is a simple pattern that checks for the constant value. Consider the following example: if the Person object is null, it will return and exit the body method.

The Person class is as follows:

class Person 
{ 
  public int ID { set; get; } 
  public string Name { get; set; }

  public DateTime DOB { get; set; } 
} 

In the preceding code snippet, we have a Person class that contains three properties, namely ID, Name, and DOB (Date of Birth).

The following statement checks for the person object with a null constant value and returns it if the object is null:

if (person is null) return;