Retrieve Child Collections

Configuring **one-to-many** relationships in Umbraco UI Builder, the backoffice UI builder for Umbraco.

Retrieving child collections in one-to-many relationships with UI Builder, can be achieved with the support of child repositories. One-to-many relations are where one parent entity of a collection is associated with multiple entities from another.

Models Representation

The models would look like this:

[TableName("Students")]
[PrimaryKey("Id")]
public class Student
{
    [PrimaryKeyColumn]
    public int Id { get; set; }

    public string FirstName { get; set; }

    public string LastName { get; set; }

    public string Email { get; set; }
}

[TableName("StudentProjects")]
[PrimaryKey("Id")]
public class StudentProject
{
    [PrimaryKeyColumn]
    public int Id { get; set; }

    public string Name { get; set; }

    public int StudentId { get; set; }
}

Child Repositories

You can create child repository instances via the IRepositoryFactory and use them to retrieve information from the child collection.

public class StudentProjectController : Controller
{
    private readonly IRepositoryFactory _repositoryFactory;

    public StudentProjectController(IRepositoryFactory repositoryFactory)
    {
        _repositoryFactory = repositoryFactory;
    }

    public IActionResult Index(int projectId)
    {
        var childRepository = _repositoryFactory.GetChildRepository<int, StudentProject, int>(projectId);

        var list = childRepository.GetAll();

        var count = childRepository.GetCount();

        var listPaged = childRepository.GetPaged();

        return View(list);
    }
}