Reflection on static members of a generic type

Question

I have the following class.

class MyClass<T>
{
    private static List<T> _Values;
    public static List<T> Values
    {
        get { return (_Values = _Values ?? new List<T>()); }
    }
}

I have used it several times like this.

MyClass<Int32>.Values.Add(1);
MyClass<String>.Values.Add("1");

Is there any possibility to retrieve all Lists of all types that have ever been used and are in the memory now using reflection?

Something like

var lists = typeof(MyClass<>)
    .MemoryOccurrences()
    .Select(x => x.GetStaticVariable("Values")); // two lists expected in this case

Do you have a list of types like `int` and `string` that your application uses for `T`? — Yacoub Massad, Jan 02 '16 at 01:40
@YacoubMassad, no, these types are deemed to be classes and there can be many of them. According to the question that is provided in the first comment, it doesn't see to be possible. — Oybek, Jan 02 '16 at 01:42

score 1 · Answer 1 · answered Jan 02 '16 at 04:13

You can't do it with Reflection, but you can do it create a instance holder, like this

public class MyClassInstanceHolder
{
    private static Dictionary<Type, object> Instances { get; } = new Dictionary<Type, object>();

    public static List<T> GetNewOrExistent<T>()
    {
        var type = typeof(MyClass<T>);
        if (Instances.ContainsKey(type))
            return (List<T>)Instances[type];

        Instances.Add(type, MyClass<T>.Values);
        return MyClass<T>.Values;
    }

    public static IEnumerable<object> GetAllInstances() => Instances.Select(i => i.Value);
}

Then you can still use it with a small change

MyClassInstanceHolder.GetNewOrExistent<int>().Add(1);
MyClassInstanceHolder.GetNewOrExistent<int>().Add(2);
MyClassInstanceHolder.GetNewOrExistent<int>().Add(3);
MyClassInstanceHolder.GetNewOrExistent<string>().Add("string value");

And you can all get all instances values.

foreach (var allInstance in MyClassInstanceHolder.GetAllInstances())
{
    foreach (var o in (IEnumerable) allInstance)
        Console.WriteLine(o);
    Console.WriteLine("=================");
}

1

2

3

=================

string value

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Reflection on static members of a generic type

1 Answers1