将项添加到通用列表 [英] Adding item to a generic list

问题描述

我正在尝试从数据库中选择数据，但我收到重复的数据。



情景是：

我有2条记录在这个数据库中：



RoomId RoomTitle RoomName Room价格

1房间1房间1 200

2房间2房间2 250



这是我在C＃中的代码：

I am trying to select data from database but I am getting duplicate data.

The Scenario is :
I have 2 records in the database like this:

RoomId RoomTitle RoomName RoomPrice
1 Room1 Room1 200
2 Room2 Room2 250

And this is my code in C#:

public static List<RoomInfo> GetAvailRoom(string Checkin, string Checkout)
   {
       DateTime CheckinDate = DateTime.ParseExact(Checkin, "M/dd/yyyy", CultureInfo.InvariantCulture.DateTimeFormat);
       DateTime CheckoutDate = DateTime.ParseExact(Checkout, "M/dd/yyyy", CultureInfo.InvariantCulture.DateTimeFormat);

       List<RoomInfo> lstRooms = RoomInfo.GetRooms();
       List<RoomImage> lstRoomImages = new List<RoomImage>();
       List<RoomInfo> lstRoomsNew = new List<RoomInfo>();
       RoomInfo _RoomInfo = new RoomInfo();

       foreach (var roomitems in lstRooms)
       {
           _RoomInfo.Checkin = CheckinDate;
           _RoomInfo.Checkout = CheckoutDate;
           var roomAvailable = _RoomInfo.GetAvailableRoomByDate();

               foreach (var items in roomAvailable)
               {

                   _RoomInfo.RoomId = items.RoomId;
                   _RoomInfo.RoomTitle = items.RoomTitle;
                   _RoomInfo.RoomName = items.RoomName;
                   _RoomInfo.RoomPrice = items.RoomPrice;
                   _RoomInfo.RoomDescription = items.RoomDescription;
                   _RoomInfo.IsBookButton = items.IsBookButton;
                   if (_RoomInfo.RoomId > 0)
                   {
                    RoomImage _RoomImage = new RoomImage();
                   _RoomImage.RoomId = _RoomInfo.RoomId;
                   var LstOfImages = _RoomImage.GetRoomImagesByRoomId();

                   HttpContext.Current.Session["RoomId"] = _RoomInfo.RoomId;

                   foreach (var images in LstOfImages)
                   {

                       _RoomInfo.RoomImageId = images.RoomImageId;
                       _RoomInfo.RoomId = images.RoomId;
                       _RoomInfo.LSTImages = LstOfImages;
                   }

                  }
                  else
                  {

                      string lblMsgError = string.Empty;
                      lblMsgError += string.Format("<div id=\"ShowError\" class=\"NotificationError\">{0}</div>", _RoomInfo.RoomNotAvailable);

                  }
           }

           lstRoomsNew.Add(_RoomInfo); // Here is the problem I think.


       }

       return lstRoomsNew;
     }

没问题，我只获得第二条记录一式两份，意味着2次：

2房间2房间250 250

现在的问题是，只需检查这一行：lstRoomsNew.Add（_RoomInfo）; //这就是我想的问题。



我认为这是有问题的地方。在那一行。



请有人帮忙。

No the problem is, I am getting the second record only in duplicate, means 2 times:
2 Room2 Room2 250
Now the thing is, just check on this line: lstRoomsNew.Add(_RoomInfo); // Here is the problem I think.

I think it is where there is a problem. On that line.

Please can someone help.

推荐答案

问题很简单：你只创建一个房间的一个实例 - 但随后你改变其中的数据：

The problem is simple: you only create one instance of a room - but then you change the data within it:

RoomInfo _RoomInfo = new RoomInfo();

foreach (var roomitems in lstRooms)
{
    _RoomInfo.Checkin = CheckinDate;
    ...
    lstRoomsNew.Add(_RoomInfo); // Here is the problem I think.
}

因此，当你查看你的收藏时，你会看到两次相同的数据。



在循环中移动实例创建：

So when you look at your collection, you see the same data twice.

Move the instance creation inside the loop:

foreach (var roomitems in lstRooms)
{
    RoomInfo _RoomInfo = new RoomInfo();
    _RoomInfo.Checkin = CheckinDate;
    ...
    lstRoomsNew.Add(_RoomInfo); // Here is the problem I think.
}

它会做你想要的 - 因为现在你为每组数据创建了新的房间。

And it'll do what you want - because now you create new rooms for each set of data.

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