public class MyObj
{
    public string Name { get; set; }
    public int ID { get; set; }
}

再数据库查询后的datatable我们想把它转成List<object>

我们可以这样做

private List<MyObj> test(DataTable dt)
{

    var convertedList = (from rw in dt.AsEnumerable()
        select new MyObj() 
        {
            ID = Convert.ToInt32(rw["ID"]),
            Name = Convert.ToString(rw["Name"])
        }).ToList();

    return convertedList;
}

如果不确定object的类型，那我们可以这样做

private List<object> GetListByDataTable(DataTable dt)
{

    var reult = (from rw in dt.AsEnumerable()
        select new
        {
            Name = Convert.ToString(rw["Name"]),
            ID = Convert.ToInt32(rw["ID"])
        }).ToList();

    return reult.ConvertAll<object>(o => (object)o);
}