c# - 如何遍历 Linq 中 .select 语句中的所有元素

Question

我正在尝试打印“书名，作者姓名”(有些书有多个作者) Linq 代码下方仅打印第一作者。如何打印与一本书关联的所有作者？

 List<string> books = docs.Descendants(name)

   .Select(x => new {
       Title = (string)x.Element(ns+"TITLE"),
           Author = x.Element(ns+"INTEL_AUTH")
        })
.Select(x => new {
           Title = x.Title,
           FirstName = (string) x.Author.Element(ns+"FNAME"),
           MiddleInitial = (string) x.Author.Element(ns+"MNAME"),
           LastName = (string) x.Author.Element(ns+"LNAME"),
        })
.Select(x => string.Format("{0}: {1} {2} {3}",
                           x.Title,
                           x.FirstName, x.MiddleInitial, x.LastName))
.ToList();

for (int i = 0; i < books.Count; i++)
{       
   Response.Write("--" + books[i] + "<BR />" );      
}

XML 这是xml代码。 测试 1 约翰 美国能源部 约翰 飞碟

 <INTEL_AUTH ID="10">
 <FNAME>JO</FNAME>
 <MNAME></MNAME>
 <LNAME>JO</LNAME>
 <INTEL_AUTH>
 </INTEL>

  <INTEL>
  <TILE> LEARNING LINQ</TITLE>
  <INTEL_AUTH ID="2">
  <FNAME> SHELLY</FNAME>
  <MNAME></MNAME>
  <LNAME>SHELLY</LNAME>
  <INTEL_AUTH iD="3">
  <FNAME>CHRIS</FNAME>
  <MNAME></MNAME>
  <LNAME>MADISON</LNAME>
  </INTEL_AUTH>


  </INTEL>
  </RECORD>
  </XML>

我希望输出像 : (TITLE) : ALL AUTHORS WHO WROTE THAT BOOK

测试 1:JOHN DOE、JOHN SKEET、JO JO 学习 LINQ:SHELLY SHELLY，CHRIS MADISON

Answer 1

不清楚您是想要一个包含多个作者的结果，还是每个作者一个结果，或者您希望如何在 List<string> 中表示它.我怀疑这会做你需要的:

var query = docs.Descendants(name)
    // First get the relevant elements out of the main book element
    .Select(x => new {
        Title = (string) x.Element(ns + "TITLE"),
        Authors = x.Elements(ns + "INTEL_AUTH")
     })
    // Now transform them from LINQ to XML into plain objects
    .Select(x => new {
        Title = x.Title,
        Authors = x.Authors.Select(a => new {
            FirstName = (string) a.Element(ns + "FNAME"),
            MiddleInitial = (string) a.Element(ns + "MNAME"),
            LastName = (string) a.Element(ns + "LNAME")
        })
     });

 foreach (var book in query)
 {
     Console.WriteLine("{0}:", book.Title);
     foreach (var author in book.Authors)
     {
         Console.WriteLine("  {0} {1} {2}",
                           author.FirstName, author.MiddleInitial,
                           author.LastName);
     }
 }