Question

我正在尝试进行一次查询以在5个不同的表中点击数据库，以便在一个viewmodel中发送到我的视图。这是我的数据类。

public partial class Table_Parts_Warehouse
{
    public int CQPN { get; set; }
    public int CATEGORY { get; set; }
    public int SUBCATEGORY { get; set; }
    public string DESCRIPTION { get; set; }
    public int QTY { get; set; }
    public Nullable<int> MINSTK { get; set; }
    public Nullable<int> MAXSTK { get; set; }
    public Nullable<decimal> COST { get; set; }
}

public partial class Table_Parts_Order
{
    public int ORDERID { get; set; }
    public System.DateTime DATE { get; set; }
    public bool STATUS { get; set; }
    public string PONO { get; set; }
    public string INVOICENO { get; set; }
    public string QUOTENO { get; set; }
    public int COMPANYID { get; set; }
    public Nullable<decimal> COST { get; set; }
}

public partial class Table_Parts_OrderPart
{
    public int ORDERPARTID { get; set; }
    public int ORDERID { get; set; }
    public int CQPN { get; set; }
    public int ORDERQTY { get; set; }
    public Nullable<int> RECVQTY { get; set; }
    public string PARTNO { get; set; }
}

public partial class Table_Parts_Vendor
{
    public int COMPANYID { get; set; }
    public string PHONENO { get; set; }
    public string COMPANYNAME { get; set; }
}

public partial class Table_Parts_Part
{
    public int PARTID { get; set; }
    public int CQPN { get; set; }
    public string PARTNO { get; set; }
    public decimal COST { get; set; }
    public int COMPANYID { get; set; }
    public int QTY { get; set; }
}

我的viewmodel类在这里，所有这些类，订单类是单个订单条目，但其余的都是该订单的关联零件和数据的列表。

public class OrderDetailsViewModel
{
    public Table_Parts_Order tb_parts_order { get; set; }
    public List<Table_Parts_OrderPart> tb_parts_orderpart { get; set; }
    public List<Table_Parts_Vendor> tb_parts_vendor { get; set; }
    public List<Table_Parts_Warehouse> tb_parts_warehouse { get; set; }
    public List<Table_Parts_Part> tb_parts_part { get; set; }
}

在我的视图控制器中，我尝试对所有这些进行1次查询并一次性选择它们。我可以使用相同的查询单独执行此操作并选择表，然后.ToList（）工作正常，但我打了5次而不是一次。需要帮助来选择此查询中的列表。

public ActionResult PartsOrderDetails(int? id)
{
    if (id == null)
        return new HttpStatusCodeResult(HttpStatusCode.BadRequest);


    OrderDetailsViewModel vm = new OrderDetailsViewModel();

    vm = (from a in db.Table_Parts_Warehouse
              join b in db.Table_Parts_OrderPart
              on a.CQPN equals b.CQPN
              join c in db.Table_Parts_Part
              on b.PARTNO equals c.PARTNO
              join d in db.Table_Parts_Vendor
              on c.COMPANYID equals d.COMPANYID
              join e in db.Table_Parts_Order
              on b.ORDERID equals e.ORDERID
              orderby a.CQPN ascending
              where b.ORDERID == id
              select new OrderDetailsViewModel
              {
                  tb_parts_order = e,
                  tb_parts_orderpart = b, //(.ToList)
                  tb_parts_vendor = d, //(.ToList)
                  tb_parts_warehouse = a, //(.ToList)
                  tb_parts_part = c //(.ToList)
              });

    return View(vm);

}

这显然不起作用，因为我无法获得这样的列表。我已经看到人们在select new中进行另一个查询，但我不想重复查询5次。什么是实现这一目标的最佳方式？

Answer 1

这是我以前的项目的代码片段。你可以从这个例子中得到一个好主意。最好不要在控制器中进行查询以进行调试。我创建了一个服务类。

服务类

   public static List<RetrivalQueryModel> GetPartner()
    {
        List<RetrivalQueryModel> partnerList = new List<RetrivalQueryModel>();
        using (SqlConnection connection = new SqlConnection(_constring))
        {
            StringBuilder sqlCommandBuilder = new StringBuilder();

            sqlCommandBuilder.Append("SELECT Partner.PartnerId, (Staff.Forename+ ','+Staff.Surname) AS Name FROM tblpartner Partner JOIN tblstaff Staff ON Staff.StaffId = Partner.StaffId Where Partner.Suspended = 0 ORDER BY Staff.Forename , Staff.Surname "); //will search only for active partners, take away Partner.Suspended to show all
            SqlCommand sqlCommand = new SqlCommand(sqlCommandBuilder.ToString(), connection);
            try
            {
                connection.Open();
                SqlDataReader reader = sqlCommand.ExecuteReader();
                while (reader.Read())
                {
                    try
                    {
                        RetrivalQueryModel partner = new RetrivalQueryModel();
                        partner.Partner = reader.GetString(1);
                        partner.PartnerId = reader.GetInt32(0);

                        partnerList.Add(partner);
                    }
                    catch (Exception ex)
                    {
                        log.Error(ex);
                    }
                }
                reader.Close();
                connection.Close();
            }
            catch (Exception ex)
            {
                log.Error(ex);
            }
        }
        return partnerList;
    }

控制器

public JsonResult GetPartnerList()
    {
        List<RetrivalQueryModel> rtnList = PMService.GetPartner();
        JsonResult result = new JsonResult();
        result.Data = rtnList;
        result.JsonRequestBehavior = JsonRequestBehavior.AllowGet;
        return result;
    }

<强>模型

namespace EngagementRetrival.Models
{
public class RetrivalQueryModel
{
    public string JobStatus { get; set; }
    public int JobStatusID { get; set; }
    public string Market { get; set; }
    public int MarketId { get; set; }
    public string Office { get; set; }
    public int OfficeId { get; set; }
    public string Partner { get; set; }
    public int PartnerId { get; set; }
}

}

Answer 2

对于任何关心的人，我都想到了这一点。实际上很容易。请勿使用select new OrderDetailsViewModel尝试在您的linq查询中执行此操作。只需将查询作为列表抓取，迭代它们并添加到列表中。

public ActionResult PartsOrderDetails(int? id)
{
    if (id == null)
        return new HttpStatusCodeResult(HttpStatusCode.BadRequest);

    OrderDetailsViewModel vm = new OrderDetailsViewModel();

    var query = (from a in db.Table_Parts_Warehouse
                 join b in db.Table_Parts_OrderPart
                 on a.CQPN equals b.CQPN
                 join c in db.Table_Parts_Part
                 on b.PARTNO equals c.PARTNO
                 join d in db.Table_Parts_Vendor
                 on c.COMPANYID equals d.COMPANYID
                 orderby a.CQPN ascending
                 where b.ORDERID == id
                 select new
                 {
                     tb_parts_orderpart = b,
                     tb_parts_vendor = d,
                     tb_parts_warehouse = a,
                     tb_parts_part = c
                 }).ToList();

    vm.tb_parts_order = db.Table_Parts_Order.Find(id);
    vm.tb_parts_orderpart = new List<Table_Parts_OrderPart>();
    vm.tb_parts_part = new List<Table_Parts_Part>();
    vm.tb_parts_vendor = new List<Table_Parts_Vendor>();
    vm.tb_parts_warehouse = new List<Table_Parts_Warehouse>();

    for (int i = 0; i < query.Count(); i++)
    {
        vm.tb_parts_orderpart.Add(query[i].tb_parts_orderpart);
        vm.tb_parts_part.Add(query[i].tb_parts_part);
        vm.tb_parts_vendor.Add(query[i].tb_parts_vendor);
        vm.tb_parts_warehouse.Add(query[i].tb_parts_warehouse);
    }

   return View(vm);
}

LINQ查询到MVC Viewmodel多个表和列表

2 个答案: