how can i fix this error CS7036? its an issue comunicating a callback from a server

Hello guys,

I’m doing a stock list that fill itself with the data of the tables in a server (like an inventory system for a mmorpg). for that, I’m using a Web.cs that call the info from a php file and a Stock.cs that is using the info obtained to create an item Stock for each StockID and fill the name with the Name of the item.

the error that I’m obtaining is:

Error CS7036 There is no argument given that corresponds to the required formal parameter 'callback' of 'Web.GetStockID(string, Action)'

at my Web.cs

i think that is because Stock.cs. I've been checking and i cant spot why, please help me.

thanks.

PD: im leaving the scrips below (first web, and then stock):

WEB>

 // Start is called before the first frame update
 void Start()
 {
     StartCoroutine(GetDate());
     StartCoroutine(GetUsers());
 }


 public void ShowStock()
 {
     StartCoroutine(GetStockID(Main.Instance.UserInfo.UserId));

 }
 IEnumerator GetDate() //ordena los mensajes en forma de lista
 {

     using (UnityWebRequest webRequest = UnityWebRequest.Get("http://localhost/ar_demo/GetDate.php"))
     {
         // Request and wait for the desired page.
         yield return webRequest.SendWebRequest();



         if (webRequest.isNetworkError)
         {
             Debug.Log(webRequest.error);
         }
         else
         {
             //Show Results as Text
             Debug.Log(webRequest.downloadHandler.text);

             //Or retrieve results as binary

             byte[] results = webRequest.downloadHandler.data;
         }
     }
 }




 IEnumerator GetUsers() //ordena los mensajes en forma de lista
 {

     using (UnityWebRequest webRequest = UnityWebRequest.Get("http://localhost/ar_demo/GetUser.php"))
     {
         // Request and wait for the desired page.
         yield return webRequest.SendWebRequest();



         if (webRequest.isNetworkError)
         {
             Debug.Log(webRequest.error);
         }
         else
         {
             //Show Results as Text
             Debug.Log(webRequest.downloadHandler.text);

             //Or retrieve results as binary

             byte[] results = webRequest.downloadHandler.data;
         }
     }
 }



 public IEnumerator Login(string Username, string Password) //ordena los mensajes en forma de lista
 {
     WWWForm form = new WWWForm();
     form.AddField("loginUser", Username);
     form.AddField("loginPass", Password);


     using (UnityWebRequest webRequest = UnityWebRequest.Post("http://localhost/ar_demo/Login.php", form))
     {
         // Request and wait for the desired page.
         yield return webRequest.SendWebRequest();


         if (webRequest.isNetworkError || webRequest.isHttpError)
         {
             Debug.Log(webRequest.error);
         }
         else
         {
             Debug.Log(webRequest.downloadHandler.text);
             Main.Instance.UserInfo.SetCredentials(Username, Password);
             Main.Instance.UserInfo.SetID(webRequest.downloadHandler.text);




             if (webRequest.downloadHandler.text.Contains("wrong credentials")
                 || webRequest.downloadHandler.text.Contains("Username does not exist."))
             {
                 Debug.Log("Try again.");
             }

             //if we loging correctly
             else

             {
                 Main.Instance.ImmersiveMediahype.SetActive(true);
                 Main.Instance.Login.gameObject.SetActive(false);

             }

         }
     }

 }


 public IEnumerator GetStockID(string UserID, Action<string> callback) //ordena los mensajes en forma de lista  
 {


     WWWForm form = new WWWForm();
     form.AddField("UserID", UserID);

     using (UnityWebRequest webRequest = UnityWebRequest.Post("http://localhost/ar_demo/GetStockID.php", form))
     {
         // Request and wait for the desired page.
         yield return webRequest.SendWebRequest();

         if (webRequest.isNetworkError)
         {
             Debug.Log(webRequest.error);
         }
         else
         {
             //Show Results as Text

             Debug.Log(webRequest.downloadHandler.text);

             string jsonArray = webRequest.downloadHandler.text;
             
             //Call callback function to pass results
             callback(jsonArray);
         }
     }
 }


 
 public IEnumerator GetStock(string StockID, System.Action<string> callback) //, System.Action<string> callback) //ordena los mensajes en forma de lista  
 {


     WWWForm form = new WWWForm();
     form.AddField("StockID", StockID);

     using (UnityWebRequest webRequest = UnityWebRequest.Post("http://localhost/ar_demo/GetStock.php", form))
     {
         // Request and wait for the desired page.
         yield return webRequest.SendWebRequest();



         if (webRequest.isNetworkError)
         {
             Debug.Log(webRequest.error);
         }
         else
         {
             //Show Results as Text

             Debug.Log(webRequest.downloadHandler.text);

             string jsonArray = webRequest.downloadHandler.text;


             //Call callback function to pass results

             callback(jsonArray);
         }
     }
 }

Stock>

 Action<string> _createItemsCallback;
 // Start is called before the first frame update
 void Start()
 {
     _createItemsCallback = (jsonArrayString) =>
     {
         StartCoroutine(CreateItemsCoroutine(jsonArrayString));
     };


     CreateItems();
 }

 public void CreateItems(){
     string UserID = Main.Instance.UserInfo.UserId;
     StartCoroutine(Main.Instance.Web.GetStockID(UserID,_createItemsCallback));
     
 }

 IEnumerator CreateItemsCoroutine(string jsonArrayString)
 {


     //parsing the jsonArrary as an array
     JSONArray jsonArray = JSON.Parse(jsonArrayString) as JSONArray;

     for (int i = 0; i < jsonArray.Count; i++)
     {
         //create local variables

         bool isDone = false; //is it done?
         string DiscountItem = jsonArray[i].AsObject["StockID"];
         JSONObject itemNamejson = new JSONObject();

         //create a callback to get the information from web.cs

         Action<string> getDiscountCallback = (ItemName) =>
         {
             isDone = true;
             JSONArray tempArray = JSON.Parse(ItemName) as JSONArray;
             itemNamejson = tempArray[0].AsObject;
         };

         StartCoroutine(Main.Instance.Web.GetStock(DiscountItem, getDiscountCallback));

         //Wait until the callback is called from WEB (inf finish dowloading)
         yield return new WaitUntil(() => isDone == true);

         //instantiate ameObject (Item Prefab)
         GameObject stock = Instantiate(Resources.Load("PREFABS/stock") as GameObject);
         stock.transform.SetParent(this.transform);
         stock.transform.localScale = Vector3.one;
         stock.transform.localPosition = Vector3.zero;

         // fill the information

         stock.transform.Find("Name").GetComponent<Text>().text = itemNamejson["Name"];

         //continue to the next item

     }

     
 }