使用 MongoDB 将查询检索为 IQueryable

Question

I'm updating an old project that implemented the database layer as interfaces so it's easier to add a new database option. I'm currently trying to add MongoDB implementation to it and I've ran into some trouble.

The project has an interface called IDataQuery which derives from the the LINQ.IQueryable interface:

public interface IDataQuery<out T> : IQueryable<T>
{
}

It also has an interfac called IDataSession which has a Query method that returns this type of IDataQuery :

public interface IDataSession : IDisposable
{
    IDataQuery<T> Query<T>() where T : class, IDataEntity;
}

I've created a class called MongoDataSession which derives from this interface and implements the Query method like so:

public class MongoDataSession : IDataSession
{
    private IMongoDatabase m_database;

    public MongoDataSession(IMongoDatabase database)
    {
        m_database = database;
    }

    public IDataQuery<T> Query<T>() where T : class, IDataEntity
    {
        var collection = m_database.GetCollection<T>("test");

        return collection.AsQueryable<T>();
    }

    public void Dispose()
    {
        // TODO.
    }
}

However, the MongoDB AsQueryable method returns the result as IMongoQueryable . I tried to cast it to IDataQuery<T> but that didn't work.

Answer 1

Solved. I created a wrapper around IDataQuery and casted to that.