The Tests of C# have some mistakes.
First, the question description said "{Category = "Main Category", Name = "Camera 1"}", but in the example test, the Category it set is "MainCategory", it lost the space.
Second, the "Assert.AreEqual(checker.Count, 5);" statement is wrong. You should write down "Assert.AreEqual(5, checker.Count);".
And I don't know why my code can pass the example test but only get zero elements in the other tests. I don't know if there are other errors in the tests that I can't see.

Wow, I have never used System.Reflection.DynamicMethod before. Thank the author.