Modding:Basic Inventory Handling

This page was last verified for Vintage Story version 1.19.3.

Overview

The most important classes for inventory management are:

• InventoryManager: Contains multiple inventories (every player has one with different inventories). Also helps with common tasks like putting items into a valid inventory.
• IInventory: Represents an item inventory (for example the players hotbar). Contains multiple ItemSlots.
• ItemSlot: Represents a specific slot (for example the offhand slot) of an inventory. Contains the ItemStack of the slot and Methods to help transfer items to and from that slot.
• ItemStack: Contains the Item and amount of items (called StackSize), e.g. "block torch-up" and StackSize of 2, for two Torches.

Basic Inventory Handling

To get access to a players inventory, you can use the InventoryManager of the IPlayer. For example, to simply give the player a torch when joining you could use TryGiveItemStack:

private ICoreServerAPI serverApi;

public override void StartServerSide(ICoreServerAPI api)
  {
    serverApi = api;
    serverApi.Event.PlayerJoin += EventOnPlayerJoin;
  }

private void EventOnPlayerJoin(IServerPlayer player)
  {
    ItemStack torch = new ItemStack(serverApi.World.GetBlock(new AssetLocation("torch-basic-lit-up")));
    player.InventoryManager.TryGiveItemstack(torch);
  }

If we want to put it directly into the offhand we can use player.Entity.LeftHandItemSlot:

ItemStack torch = new ItemStack(serverApi.World.GetBlock(new AssetLocation("torch-basic-lit-up")));
ItemSlot offhandSlot = player.Entity.LeftHandItemSlot;
if (offhandSlot?.Empty == true)
{
  offhandSlot.Itemstack = torch;
  offhandSlot.MarkDirty(); //this is needed because otherwise the client does not get the update
}

If you need access to other inventories like e.g. the backpack inventories, you can use the InventoryManager.Inventories Property. This contains a dictionary with the name of the inventory (for example "hotbar-APlayerUID") and the corresponding inventory. Another cleaner looking way if you only need a single inventory would be the InventoryManager.GetOwnInventory() method, which appends the player uid to the classname and returns the inventory. To avoid errors when typing the classnames, check first if the classname is already in the GlobalConstants.

Because backpack inventory contains the bags as well as the slots, you have to check if it is valid to put the item there. For this you can use the ItemSlot.CanHold() method.

If for example you want to fill every empty slot in the backpack with single torches you could do the following:

Block torchBlock = serverApi.World.GetBlock(new AssetLocation("torch-basic-lit-up"));
IInventory backpack = player.InventoryManager.GetOwnInventory(GlobalConstants.backpackInvClassName);
if (backpack != null)
{
  var dummySlot = new ItemSlot(null) { Itemstack = new ItemStack(torchBlock) };
  foreach (ItemSlot bag in backpack.Where(b => b.CanHold(dummySlot) && b.Empty))
  {
    bag.Itemstack = new ItemStack(torchBlock);
    bag.MarkDirty();
  }
}

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