对 Linq 的 XML 响应答案

【问题标题】：XML Response to Linq对 Linq 的 XML 响应
【发布时间】：2017-04-14 18:52:01
【问题描述】：

我的 XML 响应如下所示：

"<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Body>
<HotelAvailResponse xmlns="http://www.juniper.es/webservice/2007/">
<AvailabilityRS Url="http://xml.bookingengine.es"
TimeStamp="20130327T14:38:54.6916528+01:00"
IntCode="lCf65bPrG+x7VDLB0IquVNQgKloRA9+HOuhfHMj0BcE=">
<Results>
<HotelResult Code="7b0LYEzfsd0HH90sd" JPCode="JP003600" DestinationZone="39303" JPDCode="JPD000014">
<HotelInfo>
<Name>Hotel Test</Name>
<Description>A spacious, quiet, light and bright hotel, with a garden and fabulous views across the city.</Description>
<Images>
<Image>http://www.bookingengine.es/images/upload_p/hoteltest.jpeg</Image>
</Images>
<HotelCategory>1 1/2 Stars</HotelCategory>
<HotelType Type="SKI">Snow</HotelType>
<Address>c/tap</Address>
</HotelInfo>
<HotelOptions>
<HotelOption RatePlanCode="dcFZbKty1cJGKeRtgxIDGUZAprp1mua8ySl4iVIZ7NVKBF/PGk8lhZlN7Hcszjs2RwUR2Dxsrv5l0cZDORKz6frEmPdibqOyV2Jg4Dxz8/bF5gqPyQR8+z1LEu8LCVlS" Status="OK">
<Board Type="AD">Bed&amp;Breakfast</Board>
<Prices>
<Price Type="S" Currency="USD">
<TotalFixAmounts Gross="353.65" Nett="353.65">
<Service Amount="321.5"/>
<ServiceTaxes Included="true" Amount="32.15"/>
<Commissions Included="true" Amount="0"/>
<HandlingFees Included="true" Amount="0"/>
<Discount Amount="-0"/>
</TotalFixAmounts>
</Price>
</Prices>
<HotelRooms>
<HotelRoom Units="1" Source="1" AvailRooms="12">
<Name>Double Room</Name>
<RoomCategory Type="DBL">Double Standard</RoomCategory>
</HotelRoom>
<HotelRoom Units="1" Source="2" AvailRooms="45">
<Name>Single</Name>
<RoomCategory Type="SGL">Single Standard</RoomCategory>
</HotelRoom>
</HotelRooms>
</HotelOption>
<HotelOption RatePlanCode="dcFZbKty1cJGKeRtgxIDGUZAprp1mua8ySl4iVIZ7NVKBF/PGk8lhZlN7Hcszjs2RwUR2Dxsrv5l0cZDORKz6frEmPdibqOyV2Jg4Dxz8/bmoX041DU9+3D3nHCEB/6vYKbVtJR2qaHwW9VnnWl/KA==" Status="OK">
<Board Type="AD">Bed&amp;Breakfast</Board>
<Prices>
<Price Type="S" Currency="USD">
<TotalFixAmounts Gross="353.65" Nett="353.65">
<Service Amount="321.5"/>
<ServiceTaxes Included="true" Amount="32.15"/>
<Commissions Included="true" Amount="0"/>
<HandlingFees Included="true" Amount="0"/>
<Discount Amount="-0"/>
</TotalFixAmounts>
</Price>
</Prices>
<HotelRooms>
<HotelRoom Units="1" Source="1" AvailRooms="12">
<Name>Double Room</Name>
<RoomCategory Type="DBL">Double Standard</RoomCategory>
</HotelRoom>
<HotelRoom Units="1" Source="2" AvailRooms="11">
<Name>Double Room</Name>
<RoomCategory Type="DBL">Double Standard</RoomCategory>
</HotelRoom>
</HotelRooms>
<AdditionalElements>
<HotelOffers>
<HotelOffer>
<Name>Basic Discount 10%</Name>
</HotelOffer>
</HotelOffers>
</AdditionalElements>
</HotelOption>
</HotelOptions>
</HotelResult>
</Results>
</AvailabilityRS>
</HotelAvailResponse>
</soap:Body>
</soap:Envelope>"

我有这个 Linq 的响应如下：

XNamespace ns = "http://schemas.xmlsoap.org/soap/envelope/";
var hotels = (from hotelData in data.Descendants(ns + "Envelope").Descendants(ns + "Body").Descendants("HotelAvailResponse").Descendants("HotelAvailResult").Descendants("Results").Descendants("HotelResult")

                      select new Hotel
                          {
                              Code = hotelData.Attribute("Code").Value,
                              JpCode =
                                  hotelData.Attributes().Any(x => x.Name == "JPCode")
                                      ? hotelData.Attribute("JPCode").Value
                                      : "",
                              DestinationZone =
                                  hotelData.Attribute("DestinationZone") != null
                                      ? hotelData.Attribute("DestinationZone").Value
                                      : string.Empty,
                              JpdCode = hotelData.Attribute("JPDCode").Value,
                              //HotelName = Convert.ToString(hotelData.Element("Item").Value),
                              //Rating = Convert.ToInt32(hotelData.Element("StarRating").Value),

                              HotelInfo = (from hi in hotelData.Descendants("HotelInfo")
                              select new HotelInfo
                                  {
                                      Name = hi.Element("Name").Value,
                                      Description = hi.Element("Description").Value,
                                      Image = (from img in hi.Descendants("Images") select new Imagez { Images = img.Element("Image").Value }).ToList(),
                                      HotelCategory = hi.Element("Name").Value,
                                      HotelType = hi.Element("Description").Value,
                                      Address = hi.Element("Description").Value,
                                  }
                                  ).ToList(),

                              HotelOptions = (from ho in hotelData.Descendants("HotelOptions")
                                                  select new HotelOptions()
                                                      {
                                                          HotelOption = ho.Element("HotelOption").Attribute("RatePlanCode").Value,
                                                          Board = ho.Element("Board").Attribute("Type").Value,
                                                          Prices = (from pr in ho.Descendants("Prices") select new Prices() { Price = pr.Element("Price").Value,
                                                          TotalFixAmounts = (from tfa in pr.Descendants("TotalFixAmounts") select new TotalFixAmounts() 
                                                          { Service = tfa.Element("Service").Attribute("Amount").Value,
                                                            ServiceTaxes = tfa.Element("ServiceTaxes").Attribute("Included").Value,
                                                            AmountServiceTaxes = tfa.Element("ServiceTaxes").Attribute("Amount").Value,
                                                            Commissions = tfa.Element("Commissions").Attribute("Included").Value,
                                                            AmountCommissions = tfa.Element("Commissions").Attribute("Amount").Value,
                                                            HandlingFees = tfa.Element("HandlingFees").Attribute("Included").Value,
                                                            AmountHandlingFees = tfa.Element("HandlingFees").Attribute("Amount").Value,
                                                            Discount = tfa.Element("Amount").Attribute("Included").Value,
                                                          }).ToList(),
                                                          }).ToList(),
                                                      }).ToList(),
                          }).ToList();
        return hotels;

我没有收到任何错误，也没有任何异常，但返回的酒店数量为 0。我是 Linq 的初学者。任何帮助将不胜感激，并且已经连续 7 小时，我正在寻求帮助并试图完成它。现在我感觉到了死胡同。

提前致谢。

【问题讨论】：

标签： c# asp.net linq xmlhttprequest linq-to-xml

【解决方案1】：

您发布的代码存在一些问题。

第一个问题是代码没有考虑分配给<HotelResult> 的命名空间。命名空间是http://wwww.juniper.es/webservice/2007/，继承自<HotelAvailResponse> 元素。您可以将命名空间视为xmlns 属性：

<HotelAvailResponse xmlns="http://www.juniper.es/webservice/2007/">

这就是您的 LINQ 查询未返回任何内容的原因 - 它正在寻找具有 XML 命名空间 http://schemas.xmlsoap.org/soap/envelope 的 <HotelAvailResponse>，并且该节点不存在，因此您得到一个空集合。每次调用Descendants 或Element 时，都需要包含命名空间（即ns + "ElementName"）。

在代码真正运行之前，第二个问题并不明显，但是下面的语句

HotelOptions = (from ho in hotelData.Descendants(ns + "HotelOption")

将导致<HotelOption> 和<Board> 仅出现一次（即1 的列表）而不是两次。 <price> 信息和 <TotalFixAmounts> 正确填充 - 我不完全确定为什么，但它可能与 <TotalFixAmounts> 的嵌套列表有关。通过将选择更改为<HotelOption> 可以轻松解决此问题，如下所示：

HotelOption = (from ho in hotelData.Descendants("HotelOption")

现在ho 将是<HotelOption> 节点及其子节点的集合，它们都将被处理，嵌套列表也将被处理。

接下来，您的 LINQ 语句存在一些问题，这些问题将引发空引用异常（假设命名空间问题已得到纠正）。它们是：

Board = ho.Element("Board").Attribute("Type").Value;

ho 是所有<HotelOptions> 节点及其子节点的集合——但<Board> 是<HotelOption> 的子节点，而<HotelOption> 本身就是<HotelOptions> 的子节点。使用 XML 时，请记住它本质上是分层的——.Element(elementName) 将访问具有该名称的 first 元素，该名称是父元素的子元素（不是孙子或更远的子元素）。一个相当简单的解决方案是在语句中添加<HotelOption>：

Board = ho.Element(ns + "HotelOption").Element(ns + "Board").Attribute("Type").Value;

这里也出现了类似的问题：

TotalFixAmounts = (from tfa in pr.Descendants("Prices") select new

pr 是<Prices> 节点的集合，但select 语句中引用的元素是<Price> 的子元素，而不是<Prices>。 Element(elementName)会得到父元素的first子节点，<Prices>除了<Price>之外没有任何子节点。

最后，没有<Amount>元素是<TotalFixAmounts>的子元素，所以下面这行也会抛出空引用异常：

Discount = tfa.Element("Amount").Attribute("Included").Value;

代替您使用的两个三元运算符，我建议使用(string) - 显式转换将安全地处理丢失的元素或属性。如果缺少元素或属性，代码不会失败，它只是没有该属性的值。

所以，把这些放在一起你会得到这个：

XNamespace ns = "http://www.juniper.es/webservice/2007/";

var hotels = (from hotelData in data.Root.Descendants(ns + "HotelResult")
              select new Hotel
              {
                  Code = (string)hotelData.Attribute("Code"),
                  JpCode = (string)hotelData.Attribute("JPCode"),
                  DestinationZone = (string)hotelData.Attribute("DestinationZone"),
                  JpdCode = (string)hotelData.Attribute("JPDCode"),
                  HotelInfo = (from hi in hotelData.Descendants(ns + "HotelInfo")
                               select new HotelInfo
                               {
                                   Name = (string)hi.Element("Name"),
                                   Description = (string)hi.Element(ns + "Description"),
                                   Image = (from img in hi.Descendants(ns + "Images")
                                            select new Imagez
                                            {
                                                Images = (string)img.Element(ns + "Image")
                                            }).ToList(),
                                   HotelCategory = (string)hi.Element(ns + "Name"),
                                   HotelType = (string)hi.Element(ns + "Description"),
                                   Address = (string)hi.Element(ns + "Description"),
                               }).ToList(),
                  HotelOptions = (from ho in hotelData.Descendants(ns + "HotelOption")
                                  select new HotelOptions
                                  {
                                      HotelOption = ho.Attribute("RatePlanCode").Value,
                                      Board = ho.Element(ns + "Board").Attribute("Type").Value,
                                      Prices = (from pr in ho.Descendants(ns + "Prices")
                                                select new Price
                                                {
                                                    Price = (string)pr.Element(ns + "Price"),
                                                    TotalFixAmounts = (from tfa in pr.Descendants(ns + "Price").Descendants(ns + "TotalFixAmounts")
                                                                       select new TotalFixAmounts
                                                                       {
                                                                           Service = tfa.Element(ns + "Service").Attribute("Amount").Value,
                                                                           ServiceTaxes = tfa.Element(ns + "ServiceTaxes").Attribute("Included").Value,
                                                                           AmountServiceTaxes = tfa.Element(ns + "ServiceTaxes").Attribute("Amount").Value,
                                                                           Commissions = tfa.Element(ns + "Commissions").Attribute("Included").Value,
                                                                           AmountCommissions = tfa.Element(ns + "Commissions").Attribute("Amount").Value,
                                                                           HandlingFees = tfa.Element(ns + "HandlingFees").Attribute("Included").Value,
                                                                           AmountHandlingFees = tfa.Element(ns + "HandlingFees").Attribute("Amount").Value
                                                                       }).ToList(),
                                                }).ToList(),
                                  }).ToList(),
              }).ToList();

请注意，对Descendants 或Element 的每个引用都包含命名空间ns。

【讨论】：