Question

我正在尝试使用Linq和XML创建一个类的实例。我在我的代码中收到以下错误，不知道如何解决它。我的代码编辑器告诉我下面代码中的“select”是罪魁祸首。我对Linq很新，所以感谢任何帮助。

无法将类型'System.Collections.Generic.IEnumerable'隐式转换为'gcDiversityVision.VisionData'。存在显式转换（您是否错过了演员？）

XElement visionXML = XElement.Parse(e.Result);

            VisionData newVisionData = new VisionData(new List<string>(visionXML.Descendants(ns + "Employee").Select(f => f.Element(ns + "EmployeeName").Value)),
                                                        new List<string>(visionXML.Descendants(ns + "Employee").Select(f => f.Element(ns + "EmployeeTitle").Value)),
                                                        new List<string>(visionXML.Descendants(ns + "Employee").Select(f => f.Element(ns + "include").Attribute("externalPath").Value)),
                                                        new List<string>(visionXML.Descendants(ns + "Employee").Select(f => f.Element(ns + "EmployeeVideo").Value)),
                                                        visionXML.Element(ns + "LinkHeaderText").Value,
                                                        visionXML.Element(ns + "ButtonLinkText").Value,
                                                        visionXML.Element(ns + "ButtonLinkURL").Value,
                                                        new List<string>(visionXML.Descendants(ns + "Links").Select(f => f.Element(ns + "LinkURL").Value)),
                                                        new List<string>(visionXML.Descendants(ns + "Links").Select(f => f.Element(ns + "LinkText").Value)),
                                                        new List<string>(visionXML.Descendants(ns + "EmployeeStoryHeaderParagraph").Select(f => f.Element(ns + "EmployeeHeader").Value)),
                                                        new List<string[]>(visionXML.Descendants(ns + "EmployeeStoryHeaderParagraph").Select(f => f.Descendants(ns + "EmployeeParagraphs").Select(ep => ep.Element(ns + "EmployeeParagraph").Value).ToArray()))
                                                    );
<c:gcDiversityVision>
<c:Employee>
  <c:EmployeeName>Employee Name 1</c:EmployeeName>
  <c:EmployeeTitle>EmployeeTitle 1</c:EmployeeTitle>
  <c:EmployeeIconImage>
    <c:include type="Image" resolve="false" sourcedFrom="local" externalPath="/global/hrit/Careers/PublishingImages/down_carat.gif" height="7" width="12" query="">/hrit/Careers/PublishingImages/down_carat.gif</c:include>
  </c:EmployeeIconImage>
  <c:EmployeeVideo>mms://msnvidweb.wmod.msecnd.net/a10026/e1/ds/us/CMG_US/CMG_Microsoft/8F036573-ADAD-40B3-B2A2-A070E6C970B2.wmv</c:EmployeeVideo>
</c:Employee>
<c:Employee>
  <c:EmployeeName>Employee Name 2</c:EmployeeName>
  <c:EmployeeTitle>Employee Title 2</c:EmployeeTitle>
  <c:EmployeeIconImage>
    <c:include type="Image" resolve="false" sourcedFrom="local" externalPath="/global/hrit/Careers/PublishingImages/2nav_bg.png" height="29" width="2" query="">/hrit/Careers/PublishingImages/2nav_bg.png</c:include>
  </c:EmployeeIconImage>
  <c:EmployeeVideo>mms://msnvidweb.wmod.msecnd.net/a10026/e1/ds/us/CMG_US/CMG_Microsoft/BE4A3DF0-15FB-4610-A478-F681FCBE2DFA.wmv</c:EmployeeVideo>
</c:Employee>
<c:VisionParagraph>
  <c:VisionHeaderParagraph>
    <c:VisionHeader>Vision Header 1</c:VisionHeader>
    <c:VisionParagraphs>
      <c:VisionParagraph>Vision Paragraph 1.1</c:VisionParagraph>
    </c:VisionParagraphs>
    <c:VisionParagraphs>
      <c:VisionParagraph>Vision Paragraph 1.2</c:VisionParagraph>
    </c:VisionParagraphs>
  </c:VisionHeaderParagraph>
  <c:VisionHeaderParagraph>
    <c:VisionHeader>Vision Header 2</c:VisionHeader>
    <c:VisionParagraphs>
      <c:VisionParagraph>Vision Paragraph 2.1</c:VisionParagraph>
    </c:VisionParagraphs>
    <c:VisionParagraphs>
      <c:VisionParagraph>Vision Paragraph 2.2</c:VisionParagraph>
    </c:VisionParagraphs>
  </c:VisionHeaderParagraph>
</c:VisionParagraph>
<c:Footer>
  <c:Button>
    <c:ButtonLinkText>Button Link Text</c:ButtonLinkText>
    <c:ButtonLinkURL>http://www.bing.com/</c:ButtonLinkURL>
  </c:Button>
  <c:LinkHeaderText>Link Text 2</c:LinkHeaderText>
  <c:Links>
    <c:LinkText>Link Text 1</c:LinkText>
    <c:LinkURL>http://www.bing.com/</c:LinkURL>
  </c:Links>
  <c:Links>
    <c:LinkText>Link Text 2</c:LinkText>
    <c:LinkURL>http://www.bong.com/</c:LinkURL>
  </c:Links>
  <c:Links>
    <c:LinkText>Link Text 3</c:LinkText>
    <c:LinkURL>http://www.bing.com/</c:LinkURL>
  </c:Links>
  <c:Links>
    <c:LinkText>Link Text 4</c:LinkText>
    <c:LinkURL>http://www.bong.com/</c:LinkURL>
  </c:Links>
</c:Footer>

Answer 1

您已告知它为文档中的每个 VisonData元素创建一个新的gcDiversityVision。因此，结果是一系列VisionData个对象。

你究竟想做什么 - 创造一个，或创造多少？有很多选择 - 如果您向我们提供有关您尝试做什么的更多信息，我们可以为您提供更多帮助。

假设您拥有VisionData类，我还建议您编写静态VisionData.FromXElement方法（或将其放在其他位置），以便您的查询不是那么大。

编辑：好的，根据评论，听起来你根本不想要LINQ查询。只是：

XElement root = visionXml.Root;
VisionData newVisionData = new VisionData(...);

顺便说一句，如果您使用ToList扩展方法而非new List<string>(...)，则可能会使查询更简单一些。或者更改VisionData构造函数以接受IEnumerable<string>类型的参数而不是List<string>，因此您无需在构造函数调用中进行转换

Answer 2

我认为您可能需要修改您的查询，如：

List<VisionData> newVisionData = (from data in visionXML.Descendants(ns + "gcDiversityVision")
                            select new VisionData(new List<string>(data.Descendants(ns + "Employee").Select(f => f.Element(ns + "EmployeeName").Value)),
                                            new List<string>(data.Descendants(ns + "Employee").Select(f => f.Element(ns + "EmployeeTitle").Value)),
                                            new List<string>(data.Descendants(ns + "Employee").Select(f => f.Element(ns + "include").Attribute("externalPath").Value)),
                                            new List<string>(data.Descendants(ns + "Employee").Select(f => f.Element(ns + "EmployeeVideo").Value)),
                                            data.Element(ns + "LinkHeaderText").Value,
                                            new List<string>(data.Descendants(ns + "Links").Select(f => f.Element(ns + "LinkURL").Value)),
                                            new List<string>(data.Descendants(ns + "Links").Select(f => f.Element(ns + "LinkText").Value)),
                                            new List<string>(data.Descendants(ns + "EmployeeStoryHeaderParagraph").Select(f => f.Element(ns + "EmployeeHeader").Value)),
                                            new List<string[]>(data.Descendants(ns + "EmployeeStoryHeaderParagraph").Select(f => f.Descendants(ns + "EmployeeParagraphs").Select(ep => ep.Element(ns + "EmployeeParagraph").Value).ToArray()))
                        )).ToList();

使用Linq和XML帮助创建类的实例

2 个答案: