Mastering Visual Studio 2017

Switch statements with pattern matching

The new switch case statement pattern enhances the case blocks by comparing the value, not just by constants, but also by an expression. In C# 7.0, you can generalize the switch statement in the following manner:

• You can put switch on any type, in addition to primitive data types
• You can use patterns on case clauses
• You can have additional conditions on case clauses using the keyword when

Let's look at the following example, where we have the base Person reference passed to the switch statement:

 public static void Validate(Person person) { switch (person) { case Employee e: Console.WriteLine($"{e.Firstname} is an Employee"); break; case Customer c when (c.IsPremium): Console.WriteLine($"{c.Firstname} ...