Reflection uses the object of type Type that describes assemblies, modules and types.

Using reflection, it is possible to do many things, for example:

  • Dynamically create object instances.
  • Dynamically invoke methods.
  • Check if an object implements an interface.
  • Manipulate attributes set on objects.
  • Mock values for testing.
  • Retrieve debug information.

These are just a few things you can do with it. In this article I will show a simple example of how to use it to get descriptions of enums.

Let us say you want to display an enum in a dropdown. However, you want to have the code and description rather than just displaying the code. You can annotate your enum with the description attribute:

  1. public enum PurposeKind
  2. {
  3. Development,
  5. [Description("Functional Test")]
  6. Test,
  8. [Description("Unit Test")]
  9. UnitTest,
  10. }
And to get the description we can use reflection. I will be getting the value and description and then I will add it to a dictionary as in the following:
  1. static void Main(string[] args)
  2. {
  3. var valuesAndDescriptions = new Dictionary<PurposeKind, string>();
  5. // gets the Type that contains all the info required
  6. // to manipulate this type
  7. Type enumType = typeof(PurposeKind);
  9. // I will get all values and iterate through them
  10. var enumValues = enumType.GetEnumValues();
  12. foreach (PurposeKind value in enumValues)
  13. {
  14. // with our Type object we can get the information about
  15. // the members of it
  16. MemberInfo memberInfo =
  17. enumType.GetMember(value.ToString()).First();
  19. // we can then attempt to retrieve the
  20. // description attribute from the member info
  21. var descriptionAttribute =
  22. memberInfo.GetCustomAttribute<DescriptionAttribute>();
  24. // if we find the attribute we can access its values
  25. if (descriptionAttribute != null)
  26. {
  27. valuesAndDescriptions.Add(value,
  28. descriptionAttribute.Description);
  29. }
  30. else
  31. {
  32. valuesAndDescriptions.Add(value, value.ToString());
  33. }
  34. }
  35. }
Results:

    Development,Development
    Test,Functional Test
    UnitTest,Unit Test

See System.Type on MSDN for a reference of reflection methods.