How to call/initialize a repository in a model class?

Question

ASP.NET

I have two classes in Model>Cars.cs:

public class Cars{
    public string Name { get; set; }
    public string Number { get; set; }
}

public static class CarsHelper
{
    public static string GetOrAddCarNumber(string name)
    {
        var context = new DBContext();
        var car = context.Cars.FirstOrDefault(x => x.Name == name);
        if(car == null)
            {
                context.Cars.Add(new Cars()
                {
                    Name = name,
                    Number = ""
                });
            }

            return Cars.Number;
    }
}

I used to write But I started to study the repository pattern and rewrite the project for it, and even I don’t understand how to do it right) And is it generally right to do this? In CarsHelper, I have a couple of methods where it needs to be used. var context = new DBContext();

Answer 1

You make the CarsRepository class by type

public class CarsRepository
{
    private readonly DbContext _dbContext;
    public CarsRepository(DbContext dbContext) => _dbContext = dbContext;

    public async Task<string> GetOrAddCarNumberAsync(string carName)
    {
        var car = await _dbContext.Cars.FirstOrDefaultAsync(x => x.Name == name);
        if(car == null)
        {
            car = new Car {
                    Name = name,
                    Number = ""
            };
            _dbContext.Cars.AddAsync(car);
            await _dbContext.SaveChangesAsync():
         }
         return car.Number;
    }
}

But in general, EF already implements the Repository pattern for you, so it will be enough for you to write only extension methods for DbSets