How do I filter out <>c_DisplayClass types when going through types via reflection?

Question

I am trying to create a unit test that makes sure all of my business classes (I call them command and query classes) can be resolved with Windsor. I have the following unit test:

    [TestMethod]     public void Windsor_Can_Resolve_All_Command_And_Query_Classes()     {         // Setup         Assembly asm = Assembly.GetAssembly(typeof(IUnitOfWork));         IList<Type> classTypes = asm.GetTypes()                                     .Where(x => x.Namespace.StartsWith("MyApp.DomainModel.Commands") || x.Namespace.StartsWith("MyApp.DomainModel.Queries"))                                     .Where(x => x.IsClass)                                     .ToList();          IWindsorContainer container = new WindsorContainer();         container.Kernel.ComponentModelBuilder.AddContributor(new SingletonLifestyleEqualizer());         container.Install(FromAssembly.Containing<HomeController>());          // Act         foreach (Type t in classTypes)         {             container.Resolve(t);         }     } 

This fails with the following exception:

No component for supporting the service MyApp.DomainModel.Queries.Organizations.OrganizationByRegistrationTokenQuery+<>c__DisplayClass0 was found 

I understand that <>c__DisplayClass0 types are due to Linq being compiled, but how can I filter out these types without hardcoding the name in my Linq query?

Answer 1

I would check each Type for the System.Runtime.CompilerServices.CompilerGeneratedAttribute that is put on these.

You can use Type.IsDefined, so the code would look something like this:

foreach (Type type in classTypes) {    if (type.IsDefined (typeof (CompilerGeneratedAttribute), false))       continue;     // use type... } 

Answer 2

Apparently nested classes do not get the [CompilerGenerated] attribute applied to them.

I whipped up this simple method to deal with this scenario.

bool IsCompilerGenerated(Type t) {     if (t == null)         return false;      return t.IsDefined(typeof(CompilerGeneratedAttribute), false)         || IsCompilerGenerated(t.DeclaringType); } 

A class that exhibits this behaviour would look like this:

class SomeClass {     void CreatesADisplayClass() {         var message = "foo";          Action outputFunc = () => Trace.Write(message);          Action wheelsWithinWheels = () =>         {             var other = "bar";              Action wheel = () => Trace.WriteLine(message + " " + other);         };     } }