New Minimod: FluentGenerics–Interacting with Generic Types and Type-Definitions

Sometimes, from a concrete type, you need to find out if it implements a specific generic type or interface, and even more interesting, which concrete type arguments it uses in it’s implementation.

Since this information can be “hidden” somewhere in the type hierarchy, I created some helper extension methods that help finding this information and released them as a Minimod. What is a Minimod?

It can answer these simple questions:

Is List<Int32> an IEnumerable<T>? yes
If it is, what are the type parameters? Int32

Is Dictionary<Int32,String> an IDictionary<TKey,TValue>? yes
If it is, what are the type parameters? Int32,String

This is the test/example code generating them:

[Test]
public void PrintExamples()
{
    printExample(typeof(List<int>), typeof(IEnumerable<>));
    printExample(typeof(Dictionary<int, string>), typeof(IDictionary<,>));
}

private static void printExample(Type type, Type genTypeDef)
{
    bool isOfGenericType = type.IsOfGenericType(genTypeDef);

    Console.WriteLine("Is {0} an {1}? {2}",
                      type.GetPrettyName(),
                      genTypeDef.GetPrettyName(),
                      isOfGenericType ? "yes." : "no.");

    if (isOfGenericType)
    {
        Console.WriteLine("If it is, what are the type parameters? "
                          + type.GetGenericArgumentsFor(genTypeDef)
                                .Select(_ => _.GetPrettyName())
                                .JoinStringsWith(", "));
    }
}

Summary

The Minimod adds to System.Type the following extension methods:

  • bool IsOfGenericType(this Type type, Type genericTypeDefinition)
  • Type[] GetGenericTypesFor(this Type type, Type genericTypeDefinition)
  • Type GetGenericTypeFor(this Type type, Type genericTypeDefinition)
  • Type[] GetGenericArgumentsFor(this Type type, Type genericTypeDefinition)

Get it!

It is published to Nuget as a Minimod: NuGet gallery

Other minimods are also available there: Packages – NuGet gallery

Original source code is found at: minimod/minimods – GitHub

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