使用LINQ to XML解析XML？

Question

I try to use Linq to parse a XML in C#.

this is the XML I am parsing:

 <Credit>
 <LoanApp>

  <LoanAppRq PaymentCall="True" Personal="True" Type="Finance">

    <Applicant>
      <Personal>
        <Individuals>
          <Individual Type="Applicant">
            <GivenName>
              <FirstName>test</FirstName>
              <LastName>tester</LastName>
            </GivenName>


            <ContactInfo>

              <Address Type="Current">
                <StreetNumber>6</StreetNumber>
                <StreetName>alton AVE</StreetName>
                <City>PHILADELPHIA</City>
                <State>PA</State>
                <Zip>19142</Zip>
                <TimeAtLocation>
                  <Year>6</Year>
                  <Month>0</Month>
                </TimeAtLocation>
              </Address>

              <Address Type="Previous">
                <StreetNumber>83</StreetNumber>
                <StreetName>Main Street</StreetName>
                <StreetExtra>12</StreetExtra>
                <City>Irvine</City>
                <State>CA</State>
                <Zip>92695</Zip>
                <Country>USA</Country>
                <TimeAtLocation>
                  <Year/>
                  <Month>3</Month>
                </TimeAtLocation>
              </Address>
            </ContactInfo>

and this is my code to parse it:

        parsed_xml.LoadXml(dto.xml);
        XElement xelement = XElement.Load(stream);

        IEnumerable<XElement> Credit = xelement.Elements();
        foreach (var item in Credit)
        {

           dt.BORROWERFIRSTNAME = item.Element("LoanApp").Element("LoanAppRq").Element("Applicant").Element("Personal").Element("Individuals").Element("Individual").Element("GivenName").Element("FirstName").Value;
           dt.BORROWERLASTNAME= item.Element("LoanApp").Element("LoanAppRq").Element("Applicant").Element("Personal").Element("Individuals").Element("Individual").Element("GivenName").Element("LastName").Value;
         }

this code give me the Firstname and lastname.

1. First of all I wanted to know if this the correct way to parsing or not?
2. second if I want to get Current or previous address how I can get them? Also the previous address may not existed in some situation.

I have used this website as a reference for learning.

http://www.dotnetcurry.com/showarticle.aspx?ID=564

Answer 1

For deep XML hierarchies like yours without complex namespaces, I prefer XPathSelectElements in the System.Xml.XPath namespace.

Assuming that your xelement element has exactly the XML shown in your question, you can do:

foreach (var individual in xelement.XPathSelectElements("LoanApp/LoanAppRq/Applicant/Personal/Individuals/Individual"))
{
    // Get the first and last name.
    var BORROWERFIRSTNAME = (string)individual.XPathSelectElement("GivenName/FirstName");
    var BORROWERLASTNAME = (string)individual.XPathSelectElement("GivenName/LastName");

    // Get the XElement for the current address.
    var currentAddress = individual.XPathSelectElements("ContactInfo/Address[@Type='Current']")
                                   .FirstOrDefault();
    // Extract its properties, checking for a missing current address if necessary.
    var currentZip = (currentAddress == null ? null : (string)currentAddress.Element("Zip"));

    // Get the XElement for the previous address.
    var previousAddress = individual.XPathSelectElements("ContactInfo/Address[@Type='Previous']")
                                    .FirstOrDefault();
    // Extract its properties, checking for a missing previous address if necessary.
    var previousZip = (previousAddress == null ? null : (string)previousAddress.Element("Zip"));

    // Process the borrower names and addresses as required.
}

The equivalent in pure Linq to XML is:

foreach (var individual in xelement.Elements("LoanApp")
                                   .Elements("LoanAppRq")
                                   .Elements("Applicant")
                                   .Elements("Personal")
                                   .Elements("Individuals")
                                   .Elements("Individual"))
{
    // Get the first and last name.
    var BORROWERFIRSTNAME = (string)individual.Elements("GivenName")
                                              .Elements("FirstName")
                                              .FirstOrDefault();
    var BORROWERLASTNAME = (string)individual.Elements("GivenName")
                                             .Elements("LastName")
                                             .FirstOrDefault();

    // Get the XElement for the current address.
    var currentAddress = individual.Elements("ContactInfo").Elements("Address").Where(e => (string)e.Attribute("Type") == "Current").FirstOrDefault();
    // Extract its properties, checking for a missing current address if necessary.
    var currentZip = (currentAddress == null ? null : (string)currentAddress.Element("Zip"));

    // Get the XElement for the previous address.
    var previousAddress = individual.Elements("ContactInfo").Elements("Address").Where(e => (string)e.Attribute("Type") == "Previous").FirstOrDefault();
    // Extract its properties, checking for a missing previous address if necessary.
    var previousZip = (previousAddress == null ? null : (string)previousAddress.Element("Zip"));

    // Process the borrower names and addresses as required.
}

As you can see, it looks a bit more complicated.

Answer 2

use Descendant() and Descendants() instead

foreach (var item in Credit)
{
    dt.BORROWERFIRSTNAME = item.Descendant("FirstName").Value;
    dt.BORROWERLASTNAME= item.Descendant("LastName").Value;
}