无法从XML使用的XDocument

Question

正确加载子记录，我有两个实体

public class DbServer 
    { 
     public int ServerId { set; get; } 
     public string Name { set; get; } 
     public string Address { set; get; } 
     public List<DbDetail> DbDetails = new List<DbDetail>(); 
    } 
    public class DbDetail 
    { 
     public int DbId { set; get; } 
     public string DbName { set; get; } 
     public string UserName { set; get; } 
     public string PassWord { set; get; } 
     public List<string> ConfiguredRules = new List<string>(); 

    } 

和XML文件是根据

<DataBaseServers> 
     <DataBaseServer id ="1" title="IISDevdb1" address="iisdevdb1.mcafee.int\iisdevdb1,1515"> 
     <DataBases> 
      <database id="1" name="ebiz" userID="se_user" password="se_user_pw!"> </database> 
      <database id="2" name="oneclick" userID="se_user" password="se_user_pw!"> </database> 
      <database id="3" name="EbizStats" userID="se_user" password="se_user_pw!"> </database> 
      <database id="4" name="ebizlite" userID="se_user" password="se_user_pw!"> </database> 
      <database id="5" name="EbizErrors" userID="se_user" password="se_user_pw!"> </database> 
      <database id="6" name="machinetracker" userID="se_user" password="se_user_pw!"> </database> 
      <database id="7" name="mast" userID="se_user" password="se_user_pw!"> </database> 
      <database id="8" name="subscribe" userID="se_user" password="se_user_pw!"> </database> 
      <database id="9" name="OFFER" userID="se_user" password="se_user_pw!"> </database> 
      <database id="10" name="Session" userID="se_user" password="se_user_pw!"> </database> 
      <database id="11" name="Reconciliation" userID="se_user" password="se_user_pw!"> </database> 
      <database id="12" name="smartmessaging" userID="se_user" password="se_user_pw!"> </database> 
      <database id="13" name="Payment" userID="se_user" password="se_user_pw!"> </database> 
      <database id="46" name="SQLEye" userID="se_user" password="se_user_pw!"> </database> 
      <database id="50" name="VCAPI" userID="se_user" password="se_user_pw!"> </database>   
     </DataBases> 
     </DataBaseServer> 
     <DataBaseServer id ="3" title="172.16.216.232" address="172.16.216.232"> 
     <DataBases> 
      <database id="34" name="ebiz" userID="ebizsol" password="ebizsol_pw"> </database> 
      <database id="35" name="oneclick" userID="ebizsol1click" password="ebizsol1click_pw"> </database> 
      <database id="36" name="EbizStats" userID="ebizsol" password="ebizsol_pw"> </database> 
      <database id="37" name="ebizlite" userID="ebizlite" password="ebizlite_pw"> </database> 
      <database id="38" name="EbizErrors" userID="ebizsol" password="ebizsol_pw"> </database> 
      <database id="39" name="machinetracker" userID="mtrackuser" password="mtrackUser_pw"> </database> 
      <database id="40" name="mast" userID="mast_user" password="mast_user_pw"> </database> 
      <database id="41" name="subscribe" userID="subscribeuser" password="subscribeuser"> </database> 
      <database id="42" name="OFFER" userID="offer" password="offer_pw"> </database> 
      <database id="43" name="Session" userID="Session" password="session_pw"> </database> 
      <database id="44" name="smartmessaging" userID="ebizsol" password="ebizsol_pw"> </database> 
      <database id="45" name="Payment" userID="ebizsol" password="ebizsol_pw"> </database> 
      <database id="47" name="monitoring" userID="ebizsol" password="ebizsol_pw"> </database>   
     </DataBases> 
     </DataBaseServer>  
    </DataBaseServers> 

我试图填充两个实体在

XDocument xdoc = XDocument.Load(dbServerPath); 
var res = from dbServer in xdoc.Descendants("DataBaseServer") 
        select new DbServer 
        { 
         ServerId = Convert.ToInt32(dbServer.Attribute("id").Value), 
         Name = dbServer.Attribute("title").Value, 
         Address = dbServer.Attribute("address").Value, 
          DbDetails = (from dbDetail in xdoc.Descendants("DataBases") 
             select new DbDetail 
             { 
              DbId = Convert.ToInt32(dbDetail.Attribute("id").Value), 
              DbName = dbDetail.Attribute("name").Value 
             }).ToList() 

        }; 

但DBDetails没有得到正确填充（对象引用错误正在抛出）。

如何纠正？

Answer 1

根据您的固定错字，以下内容将适用于您的需求。

XElement xdoc = XDocument.Load("dbServerPath").Element("DataBaseServers"); 
var res = from dbServer in xdoc.Elements("DataBaseServer") 
    select new DbServer 
    { 
     ServerId = Convert.ToInt32(dbServer.Attribute("id").Value), 
     Name = dbServer.Attribute("title").Value, 
     Address = dbServer.Attribute("address").Value, 
     DbDetails = (from dbDetail in dbServer.Element("DataBases").Elements("database") 
        select new DbDetail 
        { 
         DbId = Convert.ToInt32(dbDetail.Attribute("id").Value), 
         DbName = dbDetail.Attribute("name").Value 
        }).ToList() 
    }; 

的原因，你的代码不工作是因为当你加载文档，然后开始你的LINQ查询你检查DATABASESERVER元素，但在水平，你正在寻找他们不存在，因此，你需要得到DataBaseServers元素，然后从该点加载服务器。同样的逻辑适用于数据库详细信息填充 - 您需要获取包含所有数据库详细信息记录的第一个元素。