Unity C# - Calling subclass dynamically from the base class

I'm pretty new to C# and Unity and I've trying to figure out how to handle subclasses through the base class.

I am making a card game. I've made a baseclass PlayerCard, which has subclasses such as Minion : PlayerCard.

My current structure is that PlayerCard class is instantiated like this from the deck at the start

public class PlayerDeck : MonoBehaviour{

[SerializeField] PlayerCard[] playerCardArray;

private int xPos = 2;


public void DrawCards()
{
    var cardIndex = Random.Range(0, playerCardArray.Length);
    AddCardToPlayer(playerCardArray[cardIndex]);
}

private void AddCardToPlayer(PlayerCard myCard)
{

    Vector3 cardPos = new Vector3(transform.position.x + xPos, transform.position.y, transform.position.z);
    PlayerCard newCard = Instantiate(myCard, cardPos, transform.rotation) as PlayerCard;
    xPos = xPos + 2;
}

I want my baseclass (PlayerCard) handle all mundane things such as dragging and moving the card as they will be the same for all the cards.

    private void OnMouseDown()
{
    ToggleDrag();
}

void Update()
{
    if (DraggingON) { Drag(); }
}

private void ToggleDrag()
{
    Debug.Log(playerCard);
    mouseOffset = gameObject.transform.position - Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, mouseScreenPoint.z));

    if (DraggingON)
    {
        DraggingON = false;
        SnapCardToPosition();
    }
    else
    {
        DraggingON = true;

        SnapPositionX = transform.position.x;   //Return to same x position if user has not hovered other available slot
        SnapPositionY = transform.position.y;   //Return to same y position if user has not hovered other available slot

        //Variables above will be reset to default position x/y when user has hovered a slot but then moved object away from the slot, so reset to default
        defaultPositionX = transform.position.x;
        defaultPositionY = transform.position.y;
    }
}

private void Drag()
{
    Vector3 currentMouseScreenPoint = new Vector3(Input.mousePosition.x, Input.mousePosition.y, mouseScreenPoint.z);
    Vector3 currentMousePosition = Camera.main.ScreenToWorldPoint(currentMouseScreenPoint) + mouseOffset;
    transform.position = currentMousePosition;
}

My problem lies, when SnapCardToPosition is called, which is when I want the subclass (whatever it is) to take over and handle interactions with position they were dragged into.

    private void SnapCardToPosition()
{
    Vector2 NewCardPosition = new Vector2(SnapPositionX, SnapPositionY);
    transform.position = NewCardPosition;

    //Dynamically call the subclass here?
}

So the subclass would look something like this

public class Minion : PlayerCard{
[SerializeField] int Damage = 1;


public void HandleCardPlacement()
{
    //Do something
}

I haven't figured out how this could be achieved using my structure or is it fundamentally wrong?

Solution

Make your method not private (= only this class can see this) but rather protected (= this and any derived class can see this)
And make your method either virtual (if there is a common base behavior) or abstract (if every card has to implement it from scratch) and override it in the subclass

In your base class e.g.

protected virtual void SnapCardToPosition()
{
    Vector2 NewCardPosition = new Vector2(SnapPositionX, SnapPositionY);
    transform.position = NewCardPosition;
}

and then in the subclass

protected override void SnapCardToPosition()
{
    // make sure that the base implementation is executed first
    base.SnapCardToPosition();

    // do additional stuff
}

so here each subclass can decide

whether to override the method or simply keep he default one of the base class
if it overrides it can decide if and when to call the default behavior via the base.SnapCardToPosition();