WashCommand.cs

using System;
using System.Collections.Generic;
using CitizenFX.Core;

using static CitizenFX.Core.Native.API;

namespace MyResourceNameServer.commands
{
    public class WashCommand : BaseScript
    {
        public WashCommand()
        {
            EventHandlers["onClientResourceStart"] += new Action<string>(OnClientResourceStart);
        }

        private static void OnClientResourceStart(string resourceName)
        {
            if (GetCurrentResourceName() != resourceName) return;
            
            RegisterCommand("wash", new Action<int, List<object>, string>((source, args, raw) =>
            {
                var veh = Game.PlayerPed.CurrentVehicle;
                if (veh == null)
                {
                    ShowNotification("~r~Je moet in een auto zitten om dit te gebruiken!");
                    return;
                }

                WashDecalsFromVehicle(veh.Handle, 1);
                SetVehicleDirtLevel(veh.Handle, 0f);
                ShowNotification("~g~Je auto is gewassen!");
            }), false);
        }

        private static void ShowNotification(string text)
        {
            SetNotificationTextEntry("STRING");
            AddTextComponentString(text);
            DrawNotification(false, false);
        }
    }
}