The Type class

Learn to get a Type object with typeof and GetType.

The Type class

The Type class holds runtime information about a type. It is obtained in two main ways: typeof(MyClass) for types known at compile time, obj.GetType() for the runtime type of an instance.

typeof is an operator that takes a type name. GetType is a method called on an object. Both return a Type. From this object you can list methods, properties, fields and constructors; reflection starts here.

typeof vs GetType

typeof(T) works at compile time; T must be a constant type name. obj.GetType() returns the actual runtime type of any object — it is a virtual method.

When a base class reference holds a derived instance, GetType returns the derived type. E.g. for object o = "text";, o.GetType() returns String. typeof(object) always returns Object.

Exercise Print the type name of an integer

Define int x = 42;. Get its type with Type t = x.GetType();. Print t.Name with Console.WriteLine.

Show example solution

Get the type with Type t = x.GetType();. Print the name with Console.WriteLine(t.Name);.
Example solution:
using System;

class Program
{
    static void Main()
    {
        int x = 42;
        Type t = x.GetType();
        Console.WriteLine(t.Name);
    }
}

Test yourself

What does obj.GetType() return?
- The class name as a string
- The runtime type of the object (Type)
- The object's field names
- The object's memory address
Show answer

The runtime type of the object (Type) — Correct. GetType returns the runtime type of the object as Type.

Complete the typeof call

Type t = ____(string);

Show answer

Type t = typeof(string);

Match the expression to its behavior

typeof(T)

Compile time
obj.GetType()

Runtime
typeof(int)

For a primitive
t.FullName

Gives the full name

Next lesson: GetMethods and GetProperties

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