Question

var menuQuery = repository.MenuMasters.OrderBy(c => c.Position).Select(c => new { ID = c.MenuMasterID, Position = (MenuItemPosition)c.Position + " - " + c.SitePage.Title });
ViewBag.ParentID = new SelectList(menuQuery, "ID", "Position", selectedParentId);


public int Position { get; set; }
    public MenuItemPosition MenuPosition {
        get { return (MenuItemPosition)Position; }
        set { Position = (int)value; }
    }

public enum MenuItemPosition {
    Top = 1, Main = 2, Footer = 3
}

我收到一条错误，上面写着“无法将类型'类型名称'强制转换为类型'类型名称'.LINQ to Entities仅支持转换实体数据模型基元类型。”

MenuItemPosition是“Enum”，Title是“string”

我该如何解决这个问题？非常感谢〜！

Answer 1

我认为你需要在OrderBy之后添加.ToList，因为Linq to Entities不支持字符串连接..所以你的查询看起来像：

var menuQuery = repository.MenuMasters.OrderBy(c => c.Position).ToList().Select(c => new { ID = c.MenuMasterID, Position = ((MenuItemPosition)c.Position).convertToString() + " - " + c.SitePage.Title });

Answer 2

尝试类似

的内容

var menuQuery = repository.MenuMasters.OrderBy(c => c.Position).Select(c => new { ID = c.MenuMasterID, Position = c.Position.ToString() + " - " + c.SitePage.Title });

如何选择枚举到新列表？

2 个答案: