How do I use yield in a C# RPC function?

Question

Hi. I tried to convert javascript to C# with Networking sample.

My code almost works, but some code doesn't work in NetworkLevelLoad.js (RPC function).

 //NetworkLevelLoad.js
 
 @RPC
 function LoadLevel (level : String, levelPrefix : int)
 {
     // omitted code
 
     Application.LoadLevel(level);
     yield;
     yield;
 
     // Allow receiving data again
     Network.isMessageQueueRunning = true;
     // Now the level has been loaded and we can start sending out data
     Network.SetSendingEnabled(0, true);
 
     // Notify our objects that the level and the network is ready
     for (var go in FindObjectsOfType(GameObject))
         go.SendMessage("OnNetworkLoadedLevel", SendMessageOptions.DontRequireReceiver); 
 }

I convert yield; to yield return 0;, and edited LoadLevel function to IEnumerator LoadLevel. (Of course I converted other lines to C# too.)

But at runtime, after first yield return 0, script is ended and Network.IsMessageQueueRunning is not performed. How can I edit this script for work fine?

Thanks.

Answer 1

I'm currently struggling with the same task of converting the networking example to C#

The problem is that yield containing functions must return an Enumerator but RPC functions must return void.

The following code works for me.

 [RPC]
 public void LoadLevel(string level, int levelPrefix)
 {
   StartCoroutine(loadLevel(level, levelPrefix));
 }
 
 private IEnumerator loadLevel(string level, int levelPrefix)
 {
   // omitted code
 
   Application.LoadLevel(level);
   yield return new WaitForEndOfFrame();
   yield return new WaitForEndOfFrame();
 
   // Allow receiving data again
   Network.isMessageQueueRunning = true;
   // Now the level has been loaded and we can start sending out data
   Network.SetSendingEnabled(0, true);
 
   // Notify our objects that the level and the network is ready
   foreach (GameObject go in FindObjectsOfType(typeof(GameObject)))
     go.SendMessage("OnNetworkLoadedLevel", SendMessageOptions.DontRequireReceiver);
 }

Answer 2

Answer by denewbie · Nov 17, 2010 at 10:28 AM

Meantime, I dont have my debugger with me now but I'll convert it to something like this. Does it look similar to yours?

public void LoadLevel (string level, int levelPrefix) { // omitted code

 Application.LoadLevel(level);
 yield;
 yield;

 // Allow receiving data again
 Network.isMessageQueueRunning = true;
 // Now the level has been loaded and we can start sending out data
 Network.SetSendingEnabled(0, true);

 // Notify our objects that the level and the network is ready
 foreach (GameObject go in FindObjectsOfType(GameObject))
     go.SendMessage("OnNetworkLoadedLevel", SendMessageOptions.DontRequireReceiver);

Add comment · Show 3 · Share

Kichang-Kim · Nov 19, 2010 at 07:51 AM 0

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thanks for reply. but "yield;" occured error in C#.

Peter G · Feb 12, 2011 at 02:21 PM 0

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You cannot do coroutines like that in C#. You must return IEnumerator and the yield syntax is as follows "yield return 'value';" And, never "yield return 0;". There is an unnecessary memory allocation. Return null ins$$anonymous$$d.

Kichang-Kim · Jul 05, 2012 at 04:38 AM 0

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Thanks Peter G

Answer 3

this is one major mind fuck thanks to c# being nearly useless, and javascript being well, javascript.

so i'm assuming we're all working off of the same code, and in order to fix the problem you need to make the following changes:

 [RPC]
 public void LoadLevel(string level, int levelPrefix)
 {
   StartCoroutine(loadLevel(level, levelPrefix));
 }
     
 private IEnumerator loadLevel (string level, int levelPrefix)
 {
         
     showLobby = false;
     Debug.Log("Loading level " + level + " with prefix " + levelPrefix);
     lastLevelPrefix = levelPrefix;
 
     // There is no reason to send any more data over the network on the default channel,
     // because we are about to load the level, thus all those objects will get deleted anyway
     Network.SetSendingEnabled(0, false);    
 
     // We need to stop receiving because first the level must be loaded.
     // Once the level is loaded, RPC's and other state update attached to objects in the level are allowed to fire
     Network.isMessageQueueRunning = false;
         
     // All network views loaded from a level will get a prefix into their NetworkViewID.
     // This will prevent old updates from clients leaking into a newly created scene.
     Network.SetLevelPrefix(levelPrefix);
     Application.LoadLevelAdditive(level);
     yield return new WaitForEndOfFrame();
     yield return new WaitForEndOfFrame();
     Debug.Log("Loading complete");
         
       
 
     Debug.Log("load level DONE");
     // Allow receiving data again
     Network.isMessageQueueRunning = true;
     // Now the level has been loaded and we can start sending out data
     Network.SetSendingEnabled(0, true);
         
     Debug.Log("sending load msg");
     // Notify our objects that the level and the network is ready
     foreach (GameObject go  in FindObjectsOfType(typeof(GameObject)) )
     {
             Debug.Log("sending load msg");
             go.SendMessage("OnNetworkLoadedLevel", SendMessageOptions.DontRequireReceiver);    
     }
 }

so level additive works and i dont know exactly why, but you need to change your function to a non RPC with return type IEnumerator so that yield will work properly. and in order to call as a RPC, make a dummy function with return type void. and start a coroutine so yield can work its magic.

How do I use yield in a C# RPC function?

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