Create XML file from collection list

Question

I have a collection string with information about customers like name, gender etc. All custumers have an id.

Now i want to create a common XML file with all customers in it. Something like example below:

<custumers>
  <custumer>
      <name></name>
       <id></id>
       <etc></etc>
  </custumer>
</custumers>

The start up with no XML file is easy, I used linq to create the xml file.

For initial creation I used following code:

try
{
    var xEle = new XElement("Customers",
    from cus in cusList
        select new XElement("Customer",
           new XElement("Name", cus.Name),
           new XElement("gender", cus.gender),
           new XElement("etc", cus.etc));
}
xEle.Save(path);

But on the point if i want to update the XML file i get some problems to get it. My approach to solve it:

Iterate over all customers in list and check for all customers if the customer.id exists in the XML.
IF not: add new customer to xml  
IF yes: update values

My code so far:

var xEle = XDocument.Load(xmlfile);
foreach (cus in cusList)
try
{
    var cids = from cid in xEle.Descendants("ID")
               where Int32.Parse(xid.Element("ID").Value) == cus.ID          
               select new XElement("customer", cus.name),
                  new XElement ("gender"), cus.gender),
                  new XELement ("etc."), cus.etc) 

        );
       xEle.Save(xmlpath);
}

If i want to rewrite it, i need to load all the data from the existing XML. I dont think, that this is a performant solution. Or i am wrong? — swtch3k, Dec 05 '16 at 12:30
It sounds like you want to add or modify a node in the middle of an XML file. An XML file is just a text stream not a database; there's no easy way to insert in the middle of a text stream. See [Adding a Line to the Middle of a File with .NET](http://stackoverflow.com/q/2044365/3744182). But to append see [Fastest way to add new node to end of an xml?](http://stackoverflow.com/q/849043/3744182) or [Appending an existing XML file with XmlWriter](http://stackoverflow.com/q/20922835/3744182). Simplest solution is to load the XML into memory, edit the node(s), and write the entire file. — dbc, Dec 05 '16 at 19:01

MrGadget · Accepted Answer · 2016-12-06T12:49:13.013

How about a different approach....

using System.IO;
using System.Text;
using System.Xml.Serialization;

public void Main()
{
    DataSet Custumers = new DataSet("Custumers");
    DataTable Custumer = new DataTable("Custumer");

    // Create the columns
    Custumer.Columns.Add("id", typeof(int)).Unique = true;
    Custumer.Columns.Add("name", typeof(string));
    Custumer.Columns.Add("gender", typeof(string));
    Custumer.Columns.Add("etc", typeof(string));

    // Set the primary key
    Custumer.PrimaryKey = { Custumer.Columns("id") };

    // Add table to dataset
    Custumers.Tables.Add(Custumer);
    Custumers.AcceptChanges();

    // Add a couple of rows
    Custumer.Rows.Add(1, "John", "male", "whatever");
    Custumer.Rows.Add(2, "Jane", "female", "whatever");
    Custumer.AcceptChanges();

    // Let's save this to compare to the updated version
    Custumers.WriteXml("Custumers_Original.xml");

    // Read in XML that contains an existing Custumer and adds a new one
    //  into a Clone of the Custumer table
    DataTable CustumerUpdate = Custumer.Clone;
    CustumerUpdate.ReadXml("Custumers_Update.xml");

    // Merge the clone table data to the Custumer table
    Custumer.Merge(CustumerUpdate);
    Custumer.AcceptChanges();

    Custumers.WriteXml("Custumers_Final.xml");
}

Custumers_Original.xml looks like this:

<?xml version="1.0" standalone="yes"?>
<Custumers>
    <Custumer>
        <id>1</id>
        <name>John</name>
        <gender>male</gender>
        <etc>whatever</etc>
    </Custumer>
    <Custumer>
        <id>2</id>
        <name>Jane</name>
        <gender>female</gender>
        <etc>whatever</etc>
    </Custumer>
</Custumers>

Custumers_Update.xml has this, making a change to John and adding George:

<?xml version="1.0" encoding="utf-8" ?>
<Custumers>
    <Custumer>
        <name>John</name>
        <id>1</id>
        <gender>male</gender>
        <etc>this is new</etc>
    </Custumer>
    <Custumer>
        <name>George</name>
        <id>3</id>
        <gender>male</gender>
        <etc>grandson</etc>
    </Custumer>
</Custumers>

After the merge, the Custumers_Final.xml contains this:

<?xml version="1.0" standalone="yes"?>
<Custumers>
    <Custumer>
        <id>1</id>
        <name>John</name>
        <gender>male</gender>
        <etc>this is new</etc>
    </Custumer>
    <Custumer>
        <id>2</id>
        <name>Jane</name>
        <gender>female</gender>
        <etc>whatever</etc>
    </Custumer>
    <Custumer>
        <id>3</id>
        <name>George</name>
        <gender>male</gender>
        <etc>grandson</etc>
    </Custumer>
</Custumers>

Nice approach, thank you! I solve it also using linq. i will check which is performing better and is more safety. — swtch3k, Dec 06 '16 at 07:28
One thing you never told us was where the new customer data would come from...that would make a difference. — MrGadget, Dec 06 '16 at 12:42

score 0 · Answer 2 · answered Dec 06 '16 at 07:33

0

Also my solution with linq:

 try
   {
      XDocument xEle = XDocument.Load(path);
      var ids = from id in xEle.Descendants("Custom")
      where id.Element("id").Value == cus.ID
         select id;

      foreach (XElement idCustom in ids) 
      {
         idCustom.SetElementValue("NewName", "NewElement");
      }
      xEle.Save(path);
      }

answered Dec 06 '16 at 07:33

swtch3k

51
1
10

This may fulfill your update requirement but doesn't add new records...just sayin'. – MrGadget Dec 06 '16 at 14:18

Create XML file from collection list

2 Answers2