Add project files.

FaKrosnoEfDataModel/Services/ServiceBase.cs

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+using AutoMapper;
+using AutoMapper.Internal;
+using FaKrosnoEfDataModel.Dtos;
+using Microsoft.EntityFrameworkCore;
+using System.Reflection;
+
+namespace FaKrosnoEfDataModel.Services
+{
+    public class ServiceBase<T> where T : DtoBase 
+    {
+        protected readonly FaKrosnoDbContext Context;
+        protected readonly IMapper Mapper;
+        protected readonly Type EntityType;
+
+        public ServiceBase(FaKrosnoDbContext context, IMapper mapper)
+        {
+            Context = context;
+            Mapper = mapper;
+            EntityType = FindEntityTypeForDto(typeof(T));
+        }
+
+        public virtual async Task<T?> GetById(int id)
+        {
+            object? entity = await Context.FindAsync(EntityType, id);
+
+            if (entity != null)
+            {
+                return (T)Mapper.Map(entity, entity.GetType(), typeof(T));
+            }
+
+            return default;
+        }
+
+        public virtual async Task<IEnumerable<T>> GetAll()
+        {
+            MethodInfo? setMethod =
+                typeof(DbContext).GetMethod("Set", Array.Empty<Type>())?.MakeGenericMethod(EntityType);
+            
+            IQueryable? dbSet = setMethod?.Invoke(Context, null) as IQueryable;
+
+            if (dbSet == null)
+            {
+                throw new InvalidOperationException("Failed to get DbSet for entity type.");
+            }
+
+            IList<object> entities = await Task.Run(() => dbSet.Cast<object>().ToListAsync());
+
+            return entities.Select(e => (T)Mapper.Map(e, e.GetType(), typeof(T)));
+        }
+
+        private Type FindEntityTypeForDto(Type dtoType)
+        {
+            IGlobalConfiguration? internalApi = Mapper.ConfigurationProvider.Internal();
+            
+            TypeMap map = internalApi.FindTypeMapFor(dtoType, null);
+
+            if (map != null)
+            {
+                return map.DestinationType;
+            }
+            
+            foreach (var typeMap in internalApi.GetAllTypeMaps())
+            {
+                if (typeMap.SourceType == dtoType)
+                {
+                    return typeMap.DestinationType;
+                }
+            }
+
+            throw new InvalidOperationException($"No mapping found for DTO type: {dtoType.Name}");
+        }
+    }
+}