Mirror/doc/Articles/Guides/Sync/SyncHashSet.md

SyncHashSet

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

A SyncHashSet can contain any supported mirror type

Usage

Add a SyncHashSet field to your NetworkBehaviour class. For example:

public class Player : NetworkBehaviour {

    [SerializeField]
    readonly SyncHashSet<string> skills = new SyncHashSet<string>();

    int skillPoints = 10;

    [Command]
    public void CmdLearnSkill(string skillName)
    {
        if (skillPoints > 1)
        {
            skillPoints--;

            skills.Add(skillName);
        }
    }
}

You can also detect when a SyncHashSet changes. This is useful for refreshing your character in the client or determining when you need to update your database.

Subscribe to the Callback event typically during Start, OnClientStart or OnServerStart for that.

Note that by the time you subscribe, the set will already be initialized, so you will not get a call for the initial data, only updates.

Note SyncSets must be initialized in the constructor, not in Startxxx(). You can make them readonly to ensure correct usage.

public class Player : NetworkBehaviour
{
    [SerializeField]
    public readonly SyncHashSet<string> buffs = new SyncHashSet<string>();

    // this will add the delegate on the client.
    // Use OnStartServer instead if you want it on the server
    public override void OnStartClient()
    {
        buffs.Callback += OnBuffsChanged;
    }

    void OnBuffsChanged(SyncHashSet<string>.Operation op, string buff)
    {
        switch (op) 
        {
            case SyncHashSet<string>.Operation.OP_ADD:
                // we added a buff, draw an icon on the character
                break;
            case SyncHashSet<string>.Operation.OP_CLEAR:
                // clear all buffs from the character
                break;
            case SyncHashSet<string>.Operation.OP_REMOVE:
                // We removed a buff from the character
                break;
        }
    }
}