ItemID

Lightweight value type that uniquely identifies an item by combining a type ID and variant ID. Provides value equality, implicit conversions, and serves as the primary key for item lookups in the ItemDatabase.

Definition

Namespace: Paragon.Townskeep.ItemSystem Assembly: Townskeep.dll

[Serializable]
public struct ItemID : IEquatable<ItemID>

Implements: IEquatable<ItemID>

Remarks

ItemID encodes two dimensions of item identity:

• TypeID — identifies the item type (e.g., "Iron Sword" = 1, "Health Potion" = 2). This maps to the factory's hash code / ItemData.ItemID.

• VariantID — identifies a specific variant within the type (e.g., variant 0 = base, variant 1 = enchanted). Defaults to 0.

The struct supports implicit conversions to/from int (TypeID only) and (int, int) tuples (TypeID + VariantID), making it ergonomic for both simple lookups and variant-aware code.

Quick Lookup

Goal	How
Create from type only	ItemID id = 5; or new ItemID(5)
Create with variant	new ItemID(5, 2) or ItemID id = (5, 2);
Get invalid sentinel	ItemID.Invalid (TypeID=-1, VariantID=-1)
Check equality	id1 == id2
Get type as int	int type = itemId; (implicit)
Decompose to tuple	(int type, int variant) = itemId; (implicit)
Display	itemId.ToString() → "(5:2)"

Fields

TypeID

The item type identifier. Readonly.

public readonly int TypeID

VariantID

The variant identifier within the item type. Readonly. Defaults to 0.

public readonly int VariantID

Methods

Constructor

public ItemID(int typeID, int variantID = 0)

Parameter	Type	Description
typeID	int	The item type identifier
variantID	int	The variant identifier (default: 0)

Equals

Value equality comparing both TypeID and VariantID.

public bool Equals(ItemID other)
public override bool Equals(object obj)

GetHashCode

Combines TypeID and VariantID via HashCode.Combine.

public override int GetHashCode()

ToString

Returns "(TypeID:VariantID)" format.

public override string ToString()

Example: new ItemID(3, 1).ToString() → "(3:1)"

Statics

Invalid

Sentinel value representing an invalid or unset item ID. Both TypeID and VariantID are -1.

public static ItemID Invalid { get; } = new ItemID(-1, -1)

Operators

Equality

public static bool operator ==(ItemID left, ItemID right)
public static bool operator !=(ItemID left, ItemID right)

Compares both TypeID and VariantID.

Implicit Conversions

From	To	What Transfers
ItemID	(int, int)	(TypeID, VariantID)
ItemID	int	TypeID only
(int, int)	ItemID	(TypeID, VariantID)
int	ItemID	TypeID, VariantID defaults to 0

Common Pitfalls

Implicit int conversion loses VariantID int type = itemId; only extracts TypeID. The VariantID is silently discarded. If you need both, use the tuple conversion: (int type, int variant) = itemId;

Invalid uses -1, not 0 ItemID.Invalid uses -1 for both fields. A default-constructed ItemID (via default(ItemID)) has TypeID=0, VariantID=0, which is a valid ID — not the same as Invalid.

Examples

Looking Up an Item

ItemID swordId = (1, 0);  // Type 1, base variant
IItemFactory<Item, ItemData> factory = ItemDatabase.GetFactory(swordId);
Item sword = factory.NetworkSpawn(swordId.VariantID);

Comparing Items

ItemID a = new ItemID(5, 0);
ItemID b = new ItemID(5, 1);

Debug.Log(a == b);         // false (different variants)
Debug.Log((int)a == (int)b); // true (same type)

See Also

• ItemData — data record containing the raw ItemID and VariantID fields

• ItemDatabase — registry using ItemID for factory lookups

• ItemFactory — factory that produces items