Интерфейс и Дженерик класс, котрый будет наследоваться

using System;

using System.Collections.Generic;

using Core.Models;

using SQLite.Net;

using System.Linq;

using SQLite.Net.Async;

using System.Threading.Tasks;

using System.Linq.Expressions;

namespace Core.Managers

{

public interface IRepository<T> where T : class, new()

{

Task<List<T>> Get();

Task<T> Get(int id);

Task<List<T>> Get<TValue>(Expression<Func<T, bool>> predicate = null, Expression<Func<T, TValue>> orderBy = null);

Task<T> Get(Expression<Func<T, bool>> predicate);

AsyncTableQuery<T> AsQueryable();

Task<int> Insert(T entity);

Task<int> Update(T entity);

Task<int> Delete(T entity);

}

public class Repository<T> : IRepository<T> where T : class, new()

{

private SQLiteAsyncConnection db;

public Repository(SQLiteAsyncConnection db)

{

this.db = db;

}

public AsyncTableQuery<T> AsQueryable() =>

db.Table<T>();

public async Task<List<T>> Get() =>

await db.Table<T>().ToListAsync();

public async Task<List<T>> Get<TValue>(Expression<Func<T, bool>> predicate = null, Expression<Func<T, TValue>> orderBy = null)

{

var query = db.Table<T>();

if (predicate != null)

query = query.Where(predicate);

if (orderBy != null)

query = query.OrderBy<TValue>(orderBy);

return await query.ToListAsync();

}

public async Task<T> Get(int id) =>

await db.FindAsync<T>(id);

public async Task<T> Get(Expression<Func<T, bool>> predicate) =>

await db.FindAsync<T>(predicate);

public async Task<int> Insert(T entity) =>

await db.InsertAsync(entity);

public async Task<int> Update(T entity) =>

await db.UpdateAsync(entity);

public async Task<int> Delete(T entity) =>

await db.DeleteAsync(entity);

}

}