Reflection (C# Programming Guide)

Reflection provides objects (of type Type) that describe assemblies, modules and types. You can use reflection to dynamically create an instance of a type, bind the type to an existing object, or get the type from an existing object and invoke its methods or access its fields and properties. If you are using attributes in your code, reflection enables you to access them. For more information, see Attributes (C# Programming Guide).

Here's a simple example of reflection using the static method GetType - inherited by all types from the Object base class - to obtain the type of a variable:

// Using GetType to obtain type information: 
int i = 42;
System.Type type = i.GetType();
System.Console.WriteLine(type);

The output is:

System.Int32

The following example uses reflection to obtain the full name of the loaded assembly.

// Using Reflection to get information from an Assembly:
System.Reflection.Assembly info = typeof(System.Int32).Assembly;
System.Console.WriteLine(info);

The output is:

mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

Note

The C# keywords protected and internal have no meaning in IL and are not used in the reflection APIs. The corresponding terms in IL are Family and Assembly. To identify an internal method using reflection, use the IsAssembly property. To identify a protected internal method, use the IsFamilyOrAssembly.

Reflection Overview

Reflection is useful in the following situations:

• When you have to access attributes in your program's metadata. See the topic Accessing Attributes With Reflection.

• For examining and instantiating types in an assembly.

• For building new types at runtime. Use classes in System.Reflection.Emit.

• For performing late binding, accessing methods on types created at run time. See the topic Dynamically Loading and Using Types.

Related Sections

For more information:

• Reflection Overview

• Viewing Type Information

• Reflection and Generic Types

• System.Reflection.Emit

• Accessing Attributes With Reflection (C# Programming Guide)

C# Language Specification

For more information, see the following sections in the C# Language Specification:

• 1.12 Attributes

• 7.5.11 The typeof operator

See Also

Concepts

C# Programming Guide

Reference

Application Domains (C# Programming Guide)

Assemblies and the Global Assembly Cache (C# Programming Guide)