无法访问IQueryable<；T>；按索引

本文关键字：索引 gt lt 访问 IQueryable | 更新日期: 2023-09-27 18:19:32

我是c#的新手。我正试图使用linq查询生成的列表（？）在订购单上构建一个表。其中一部分涉及引用该列表中的特定项目，如下所示：

using (CellOrderingDBEntities db = new CellOrderingDBEntities())
{
    var AccessoryItems = from AccessoryDescription in db.Accessories
                         join HardwareID in db.HardwareTypes
                             on AccessoryDescription.HardwareType equals HardwareID.HardwareID
                         where AccessoryDescription.DateRetired == null
                         select AccessoryDescription;
    List<Device> DevicesList = (List<Device>)Session["DevicesList"];
    Guid AccessoriesOrder = (from ServiceID in db.TypeOfServices
                                where ServiceID.ServiceType == "Accessories Order"
                                select ServiceID.ServiceID).FirstOrDefault();
    //This Int is used to build the accessories table
    int AccessoryRows = AccessoryItems.Count();
    if (SType == AccessoriesOrder)
    {
        for (int r = 0; r <= AccessoryRows; r++)
        {
            TableRow row = new TableRow();
            for (int c = 0; c < 3; c++)
            {
                TableCell cell = new TableCell();
                TextBox tb = new TextBox();
                int ai = 0;
                int ri = 0;
                tb.ID = "TextBoxRow_" + r + "Col_" + c;
                if (c == 0)
                {
                    cell.Controls.Add(tb);
                }
                else if (c == 1)
                {
                    cell.Text = AccessoryItems[ai];
                    ai++;
                }
            }
        }
    }

我被这个错误卡住了：

无法将带有[]的索引应用于类型为"System.Linq.IQueryable<数据.附件>'

我曾尝试将其转换为字符串列表，但由于某些原因，我不明白为什么它不允许我通过索引访问IQueryable。

无法访问IQueryable<；T>；按索引

您可以使用ElementAt访问序列中特定点的元素。因此，替换：

cell.Text = AccessoryItems[ai];

带有

cell.Text = AccessoryItems.ElementAt(ai) as String;

想好了：

                    var AccessoryItems = from AccessoryDescription in db.Accessories
                                     join HardwareID in db.HardwareTypes
                                     on AccessoryDescription.HardwareType equals HardwareID.HardwareID
                                     where AccessoryDescription.DateRetired == null
                                     select AccessoryDescription;
                List<Accessory> AIL = AccessoryItems.ToList();

在for循环中：

cell.Text = (string) AIL[ai].AccessoryDescription;

它起作用了！

相关文章：