join两张表的写法

	var menuroles = (from m in db.Menus
							join mr in db.MenuRoles
							on m.Id equals mr.MenuId
							where mr.RoleName == _rolename
							select new LeftMenus { Id=m.Id, ParentId=m.ParentId, Name=m.Name, Url=m.Url, Order =m.Order, MenuType =m.MenuType, MenuCss =m.MenuCss , MenuIcon =m.MenuIcon , MenuSmallCss =m.MenuSmallCss , MenuSmallValue =m.MenuSmallValue })
							.ToList();