Repository generic method GetById using eager loading

Question

I am using Entity Framework and would like to create generic GetById method in Repository class with eager loading:

Here is my method which uses lazy-lo

Answer 1

This is the update for Entity Framework Core 2.0. Also this method using the new metadata properties with EF to automatically get the first level navigation properties.

public virtual T Get(object id)
{
        var propertyName = "AddressId";

        //get all navigation properties defined for entity
        var navigationProps = _context.Model.FindEntityType(typeof(T)).GetNavigations();

        //turn those navigation properties into a string array
        var includeProperties = navigationProps.Select(p => p.PropertyInfo.Name).ToArray();

        //make parameter of type T
        var parameter = Expression.Parameter(typeof(T), "e");

        //create the lambda expression
        var predicateLeft = Expression.PropertyOrField(parameter, propertyName);
        var predicateRight = Expression.Constant(id);
        var predicate = Expression.Lambda>(Expression.Equal(predicateLeft, predicateRight), parameter);

        //get queryable
        var query = _context.Set().AsQueryable();

        //apply Include method to the query multiple times
        query = includeProperties.Aggregate(query, Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.Include);

        //return first item in query
        return query.FirstOrDefault(predicate);
}