C# IsGenericType not working as I expected

Question

In the following code we have two classes, the Parent class uses generics:

abstract class Parent<T> 
{
    public T Put(T id, char value) 
    {
        return id;
    }
}

class Child : Parent<int> 
{
    public string Get(Guid guid) 
    {
        return "aei";
    }
}

But using reflection IsGenericType on the id parameter we get False...
I think that should be True, right?

Here is my test code:

public static void Main(string[] args)
{
    foreach (var methodInfo in typeof(Child).GetMethods())
    {
        if (!methodInfo.IsVirtual && methodInfo.GetParameters().Length > 0) 
        {
            Console.WriteLine(methodInfo.Name);
            foreach (var param in methodInfo.GetParameters())
            {
                Console.Write("  " + param.Name + " IsGenericType=");
                Console.WriteLine(param.ParameterType.IsGenericType);
            }
        }
    }
}

And output:

Get
  guid IsGenericType=False
Put
  id IsGenericType=False
  value IsGenericType=False

Answer 1

Well the result is correct. Child is not generic as in

class Child<T> : Parent<T>

but derived from Parent<int>. So the signature of Child.Put is

int Put(int id, char value);

and so id is not of a generic type, but of type int.

---

Edit:

A way to get that information could be something like this:

Type childType = typeof(Child);
MethodInfo childPut = childType.GetMethod("Put");

// get the type that initially declared the method
Type declaringType = childPut.DeclaringType;

if (declaringType.IsGenericType)
{
    // get the generic type definition (not the constructed Parent<int>)
    Type genericType = declaringType.GetGenericTypeDefinition();
    MethodInfo genericMethod = genericType.GetMethod("Put");
    ParameterInfo genericParam = genericMethod.GetParameters().First();

    // use IsGenericParameter - we want to know that the type is determined
    // by a generic argument, not if that type argument itself is generic
    Console.WriteLine(genericParam.ParameterType.IsGenericParameter);
}

This outputs true for your (special) case. I don't know your requirements, for which types the method should work. As I said in the comments, to make this an algorithm that can determine this for each parameter for all cirumstances seems complicated to me.

Answer 2

Tis not a generic type, it's a generic type parameter which is not the same thing.

A generic type is SomeType<T> but T can be string or int or whatever, which are not generic types.