Typeof() vs GetType() in C#

In C#, both typeof() and GetType() are used to obtain type information, but they work differently. typeof() is a compile-time operator that returns the Type object for a specified type, while GetType() is a runtime method that returns the actual type of an object instance.

Syntax

Following is the syntax for using typeof() operator −

Type type = typeof(TypeName);

Following is the syntax for using GetType() method −

Type type = objectInstance.GetType();

Using typeof() Operator

The typeof() operator takes a type name as its argument and returns the Type object representing that type. It works at compile-time and can be used with any type name.

Example

using System;

class Program {
   static void Main() {
      Console.WriteLine(typeof(int));
      Console.WriteLine(typeof(byte));
      Console.WriteLine(typeof(string));
      Console.WriteLine(typeof(Program));
   }
}

The output of the above code is −

System.Int32
System.Byte
System.String
Program

Using GetType() Method

The GetType() method is called on an object instance and returns the actual runtime type of that object. This is particularly useful for polymorphic scenarios where the compile-time type differs from the runtime type.

Example

using System;

class Program {
   public static void Main() {
      object[] values = { (int) 100, (long) 17111, "Hello" };
      
      foreach (var value in values) {
         Type tp = value.GetType();
         
         if (tp.Equals(typeof(int)))
            Console.WriteLine("{0} is an integer data type.", value);
         else if (tp.Equals(typeof(long)))
            Console.WriteLine("{0} is a long data type.", value);
         else
            Console.WriteLine("'{0}' is of type {1}.", value, tp.Name);
      }
   }
}

The output of the above code is −

100 is an integer data type.
17111 is a long data type.
'Hello' is of type String.

Polymorphism Example

The difference between typeof() and GetType() becomes clear in inheritance scenarios −

using System;

class Animal {
   public virtual void Speak() {
      Console.WriteLine("Animal speaks");
   }
}

class Dog : Animal {
   public override void Speak() {
      Console.WriteLine("Dog barks");
   }
}

class Program {
   static void Main() {
      Animal myAnimal = new Dog();
      
      Console.WriteLine("typeof(Animal): " + typeof(Animal));
      Console.WriteLine("myAnimal.GetType(): " + myAnimal.GetType());
      Console.WriteLine("Are they equal? " + (typeof(Animal) == myAnimal.GetType()));
   }
}

The output of the above code is −

typeof(Animal): Animal
myAnimal.GetType(): Dog
Are they equal? False

Comparison

Conclusion

Use typeof() when you know the type at compile-time and want to get its Type object. Use GetType() when you need to determine the actual runtime type of an object instance, especially in polymorphic scenarios where the runtime type may differ from the declared type.