Unity UNET中引用带Network Identity对象的子对象Rpc调用报错求助

Hey there, let's break down this UNET issue you're facing. That warning pops up because UNET's network serialization (NetworkWriter) can only handle objects with a NetworkIdentity component, and your child object doesn't have one attached. Here are a few solid solutions to fix this while keeping your highlight functionality working:

Option 1: Add NetworkIdentity to the Child Object #

If it makes sense for your setup, attaching a NetworkIdentity to the child object lets you safely pass its network ID in the Rpc call:

1. Add the NetworkIdentity component to your target child object.
   • If the child is part of a server-spawned parent, make sure the parent's NetworkIdentity doesn't have "Server Only" enabled (unless you want the child to be server-side only, but that defeats the highlight purpose for clients).
   • For player-controlled objects, you might want to set the child's NetworkIdentity to use "Local Player Authority".
2. Modify your Rpc to pass the child's NetworkInstanceId instead of the object itself:

   // Server-side: Call this when raycast hits the child
   [ClientRpc]
   public void RpcHighlightChild(NetworkInstanceId childNetId)
   {
       // Client-side: Find the child using its network ID
       GameObject targetChild = NetworkServer.FindLocalObject(childNetId);
       if (targetChild != null)
       {
           // Apply your highlight material
           targetChild.GetComponent<Renderer>().material = yourHighlightMaterial;
       }
   }
   
   // When triggering the highlight from the server:
   RpcHighlightChild(hitChild.GetComponent<NetworkIdentity>().netId);
   

Option 2: Pass a Child Identifier (No Extra NetworkIdentity) #

If you don't want to add NetworkIdentity to every child (to avoid network overhead), pass a unique identifier for the child that the client can use to find it:

• Use the child's name (ensure it's unique under the parent) or its sibling index (more reliable if names might change):

  // Server-side: After raycast hit
  int childSiblingIndex = hitChild.transform.GetSiblingIndex();
  RpcHighlightChildByIndex(childSiblingIndex);
  
  // ClientRpc method
  [ClientRpc]
  public void RpcHighlightChildByIndex(int childIndex)
  {
      // Client-side: Find the child via parent transform
      if (transform.childCount > childIndex)
      {
          GameObject targetChild = transform.GetChild(childIndex).gameObject;
          targetChild.GetComponent<Renderer>().material = yourHighlightMaterial;
      }
  }
  

Option 3: Use Custom Network Messages (For More Control) #

If Rpc feels too restrictive, send a custom network message with all the info the client needs:

// Define a custom message class
public class HighlightChildMessage : MessageBase
{
    public NetworkInstanceId ParentNetId;
    public int ChildSiblingIndex;
}

// Server-side: Send the message to all clients
void SendHighlightMessage(GameObject parent, GameObject hitChild)
{
    var msg = new HighlightChildMessage
    {
        ParentNetId = parent.GetComponent<NetworkIdentity>().netId,
        ChildSiblingIndex = hitChild.transform.GetSiblingIndex()
    };
    NetworkServer.SendToAll(msg);
}

// Client-side: Register and handle the message
void Start()
{
    NetworkClient.RegisterHandler<HighlightChildMessage>(OnHighlightMessageReceived);
}

void OnHighlightMessageReceived(NetworkMessage netMsg)
{
    HighlightChildMessage msg = netMsg.ReadMessage<HighlightChildMessage>();
    GameObject parentObj = NetworkServer.FindLocalObject(msg.ParentNetId);
    
    if (parentObj != null && parentObj.transform.childCount > msg.ChildSiblingIndex)
    {
        GameObject targetChild = parentObj.transform.GetChild(msg.ChildSiblingIndex).gameObject;
        targetChild.GetComponent<Renderer>().material = yourHighlightMaterial;
    }
}

The core takeaway here is that UNET won't serialize objects without NetworkIdentity in Rpc calls. Pick the option that fits your project's structure—either add the component, pass an identifier, or use custom messages.

内容的提问来源于stack exchange，提问作者Dtb49