tmsmith / Dapper-Extensions

Dapper Extensions is a small library that complements Dapper by adding basic CRUD operations (Get, Insert, Update, Delete) for your POCOs. For more advanced querying scenarios, Dapper Extensions provides a predicate system. The goal of this library is to keep your POCOs pure by not requiring any attributes or base class inheritance.
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Reference mapper does not work properly on reads. #296

Closed a-priestley closed 2 years ago

a-priestley commented 2 years ago

Hey there! So, super simplified example of what I'm trying to do here..

Entities:

Public abstract class EntityBase
{
    public Guid Id { get; set; } = Guid.NewGuid();    
}
Public class Parent : EntityBase
{
    public string Name { get; set; } = default!;
    public Child Child { get; set; } = default!;
}

Public class Child : EntityBase
{
    public string Name { get; set; } = default!;
}

with class mappers:

public class ParentMapper: ClassMapper<Parent>
{
    public ParentMapper()
    {
        Table("Parent");

        Map(x => x.Id).Key(KeyType.Unassigned).Column("ID");
        Map(x => x.Name).Column("Name");
        Map(x => x.Child).Ignore();
        ReferenceMap(x => x.Child).Reference<Child>((c, p) => c.Id == p.Child.Id);
    }
}

public class ChildMapper: ClassMapper<Child>
{
    public ChildMapper()
    {
        Table("Child");

        Map(x => x.Id).Key(KeyType.Unassigned).Column("ID");
        Map(x => x.Name).Column("Name");
    }
}

data layer:

public async Task AddAsync<T>(T entity) where T : class
{
    await _dbConnection.InsertAsync<T>(entity, _dbTransaction);
}

^^ This maps correctly

but:

public async Task<IEnumerable<T>> GetAllAsync<T>() where T : class
{
    var result = await _dbConnection.GetListAsync<T>(transaction: _dbTransaction);
    return result;
}

^^ result.Child is null here.

I am aiming to produce a parent item containing a Child with an Id mapped to the table Parent.ChildID

If I do Map(x => x.Child.Id).Column("ChildID"); I get Linq error Sequence contains more than one matching element

Does Parent {} explicitly need ChildId so I can map the property, or is it possible to do without?

Cheers!

valfrid-ly commented 2 years ago

Hi @a-priestley .

What you need was answered here

a-priestley commented 2 years ago

Hi @a-priestley .

What you need was answered here

Ah, thank you. I will check that out!