EF Linq包含多个字符串

Question

So I'm trying to retrieve (one or more) children of some entities using EF Linq. The strange thing is that this isn't working:

public static class DbSetExtension
{
    public static IQueryable<T> Include<T>(this IDbSet<T> dbSet, params string[] paths) where T : class
    {
        foreach (var path in paths)
            dbSet.Include(path: path);

        return dbSet;
    }
}

//Usage: dbSet<Company>().Include(paths: nameof(Company.Projects))

In this case, every child is empty... But when I use this, it works:

dbSet.Include("Projects");

Does anyone know why? And what I could do to solve this?

Solution

public static IQueryable<T> Include<T>(this IQueryable<T> queryable, params string[] paths) where T : class
{
    foreach (var path in paths)
        queryable = queryable.Include(path: path);

    return queryable;
}

Answer 1

.Include doesn't actually change anything about dbSet . It returns a value, not modifies the object it's called on.

foreach(var path in paths)
{
    dbSet = dbSet.Include(path: path);
}

should work.

Answer 2

Well, by itself, this:

dbSet.Include(path: path);

doesn't alter the state of the dbSet.

So when you are returning, the include is not "included".