C# generic interface specialization

Question

I wonder if it is in any way possible to specialize generic interface methods somehow in C#? I have found similar questions, but nothing exactly like this. Now I suspect tha

Answer 1

You can do it by introducing additional type information (e.g. implementing an interface). Here is an example.

// no need to modify the original interface
public interface IStorage
{
    void Store(T data);
}

Implementation with specialization based on a generic interface

public class Storage : IStorage,
    Storage.ISpecializedFor,
    Storage.ISpecializedFor
{
    // a private interface to provide additional type info
    private interface ISpecializedFor
    {
        void Store(T data);
    }

    public void Store(T data)
    {
        // resolve specialization
        if (this is ISpecializedFor specialized)
        {
            specialized.Store(data);
        }
        else
        {
            // unspecialized implementation goes here
            Console.WriteLine("Unspecialized");
        }
    }

    // specialized implementation
    void ISpecializedFor.Store(int data)
    {
        Console.WriteLine("Specialized for int");
    }

    void ISpecializedFor.Store(double data)
    {
        Console.WriteLine("Specialized for double");
    }
}

Results

void Main()
{
    IStorage storage = new Storage();

    storage.Store("hello"); // prints "Unspecialized"
    storage.Store(42); // prints "Specialized for int"
    storage.Store(1.0); // prints "Specialized for double"
}