How do you store a reference to a property in C#?

Question

I'm creating a game, and am currently working on the Inventory system for it. I have a class to represent the player, which looks like this:

class Player {
    public Weapon WeaponSlot {get;set;}
    public Shield ShieldSlot {get;set;}
    //etc.
}

Weapon, Shield, etc are subclasses of a generic Item class:

class Item {
    //...
}

class Weapon : Item {
    //...
}

There are subclasses of Weapon, etc, but that's not important.

Anyway, I am creating a UserControl to display/modify the contents of a given inventory slot. However, I'm not sure exactly how to do that. In C++, I would use something like:

new InventorySlot(&(player.WeaponSlot));

But, I can't do that in C#.

I found the TypedReference struct, but that doesn't work since you are not allowed to make a field with one of those structs, so I couldn't store it for use later in the control.

Is reflection the only way to go, or is there some other facility that I'm not aware of?

EDIT ----

For reference, here's what I've done:

partial class InventorySlot : UserControl {
    PropertyInfo slot;
    object target;

    public InventorySlot(object target, string field) {

        slot = target.GetType().GetProperty(field);

        if (!slot.PropertyType.IsSubclassOf(typeof(Item)) && !slot.PropertyType.Equals(typeof(Item))) throw new //omitted for berevity

        this.target = target;

        InitializeComponent();
    }
    //...
}

And, it's initialized like this:

new InventorySlot(player, "WeaponSlot");

Also, regarding performance, I'm not too concerned about that. It's not a real-time game, so I only have to update the screen in response to player actions. :)

Answer 1

Every class type object is a reference in c#. Value types are declared with struct.

So for example:

Weapon w1 = new Weapon();
w2 = w1;//Does not make a copy just makes a second reference to what w1 is pointing to

If you need an input/output parameter to a function you can use ref. If you need an output parameter you can use out. If you are just passing a reference to an object that is of type class then you can just pass it and modify the class object itself.

Answer 2

I am creating a UserControl to display/modify the contents of a given inventory slot. However, I'm not sure exactly how to do that. In C++, I would use something like

It works the way you want by default. "ref" keyword is not needed either.

Answer 3

You could clone the object to achieve what you want:

public class Weapon : ICloneable
{
    public string Name;

    object ICloneable.Clone()
    {
        return this.Clone();
    }
    public Weapon Clone()
    {
        return (Weapon)this.MemberwiseClone();
    }
}

You can than do something like this to get a copy of that object with all the internal values:

Weapon w1 = new Weapon();
Weapon w2 = w1.Clone()

Answer 4

Essentially what you are creating is a property browser. Have a look at Windows Forms' PropertyGrid control (read the docs to see how it works and/or use Reflector to read the code).

The short answer is to simply use reflection. By storing a PropertyDescriptor you can get and set the value of the property member given the object instance.

Answer 5

This is the default behavior afaik

Answer 6

If you really want a reference, you can use fields instead. They can be referenced by ref.