score:1

Accepted answer
List<MenuModel> lstMenuModel = dtable.AsEnumerable()
    .GroupBy(x => new { ParentID = x["ParentID"], ParentName = x["ParentName"] })
    .Select(x => new MenuModel()
    {
        ParentID = x.Key.ParentID,
        ParentName = x.Key.ParentName,
        MenuItems = x.Select(y => new MenuItemModel()
        {
            ChildID = y["ChildID"],
            ....

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