Solved OnClick Button handle to overgive player object to another function

My code looks like this right now ( yeah I just started with writing C# ):

Code:

void OnPlayerInit(BasePlayer player)
        {
            button.onClick.AddListener(() => DoSomething(player, 1));            CommunityEntity.ServerInstance.ClientRPCEx( new Network.SendInfo() { connection = player.net.connection }, null, "AddUI", json.Replace("{something}", "Hi") );
        }
       
        public void DoSomething(BasePlayer player, int number)
        {
           // follow <.<
        }

at the error message is:

Code:

[Oxide] 2:27 PM [Debug]   at Oxide.Plugins.DoSomething.OnPlayerInit  (.BasePlayer player, System.String cmd, System.String[] args) [0x00000] in <filename unknown>:0
  at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (object,object[],System.Exception&)
  at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0 

I just figured out I could be with the player object. I really don't know how to check which player clicked which button to give this info to another function to set it then in the storedData ( < that's not the problem ).

 

Can you show me how "button" is declared, please?

I've not looked at the Community UI in too much detail yet, but the impression I got was client side buttons just ran console commands - therefore there'll be no "onClick" on the server.