SyncHashSet

SyncHashSet are sets similar to C# HashSet that synchronize their contents from the server to the clients.

A SyncHashSet can contain any supported mirror type

Usage

SyncHashSet must be declared readonly and initialized in the constructor.

Note that by the time you wire up the Action handlers, the hashset will already be initialized, so they will not get invoked for the initial data, only updates.

using UnityEngine;
using Mirror;

public class SyncHashSetExample : NetworkBehaviour
{
    public readonly SyncHashSet<string> namesHashSet = new SyncHashSet<string>();

    public override void OnStartClient()
    {
        // Add handlers for SyncHashSet Actions
        namesHashSet.OnAdd += OnItemAdded;
        namesHashSet.OnRemove += OnItemRemoved;
        namesHashSet.OnClear += OnHashSetCleared;

        // OnChange is a catch-all event that is called for any change
        // to the hashset. It is called after the specific events above.
        // Strongly recommended to use the specific events above instead!
        namesHashSet.OnChange += OnHashSetChanged;

        // Hashset is populated before handlers are wired up so we
        // need to manually invoke OnAdd for each element.
        foreach (string value in namesHashSet)
            namesHashSet.OnAdd.Invoke(value);
    }

    public override void OnStopClient()
    {
        // Remove handlers when client stops
        namesHashSet.OnAdd -= OnItemAdded;
        namesHashSet.OnRemove -= OnItemRemoved;
        namesHashSet.OnClear -= OnHashSetCleared;
        namesHashSet.OnChange -= OnHashSetChanged;
    }

    void OnItemAdded(string value)
    {
        Debug.Log($"Element added {value}");
    }

    void OnItemRemoved(string value)
    {
        Debug.Log($"Element removed {value}");
    }

    void OnHashSetCleared()
    {
        // OnHashSetCleared is called before the hashset is actually cleared
        // so we can iterate the hashset to get the elements if needed.
        foreach (string value in namesHashSet)
            Debug.Log($"Element cleared {value}");
    }

    // OnHashSetChanged is a catch-all event that is called for any change
    // to the hashset. It is called after the specific events above.
    //
    // NOTE: It's strongly recommended to use the specific events above instead!
    //
    // For OP_ADD, the value param is the NEW entry.
    // For OP_REMOVE, the value param is the OLD entry.
    // For OP_CLEAR, the value param is null / default.
    void OnHashSetChanged(SyncHashSet<string>.Operation op, string value)
    {
        switch (op)
        {
            case SyncHashSet<string>.Operation.OP_ADD:
                // value is the new entry
                Debug.Log($"Element added {value}");
                break;

            case SyncHashSet<string>.Operation.OP_REMOVE:
                // value is the old entry
                Debug.Log($"Element removed {value}");
                break;

            case SyncHashSet<string>.Operation.OP_CLEAR:
                // value is null / default
                // we can iterate the hashset to get the elements if needed.
                foreach (string name in namesHashSet)
                    Debug.Log($"Element cleared {name}");
                break;
        }
    }
}