xml serializer c# from: https://www.codeproject.com/Articles/1163664/Convert-XML-to-Csharp-Object. Use https://stackoverflow.com/questions/3187444/convert-xml-string-to-object for obtain the xml file first time

Customer.xml

<Customer>
    <CustomerID>ALFKI</CustomerID>
    <CompanyName>Alfreds Futterkiste</CompanyName>
    <ContactName>Maria Anders</ContactName>
    <ContactTitle>Sales Representative</ContactTitle>
    <Address>Obere Str. 57</Address>
    <City>Berlin</City>
    <PostalCode>12209</PostalCode>
    <Country>Germany</Country>
    <Phone>030-0074321</Phone>
    <Fax>030-0076545</Fax>
</Customer> 

CustOrders.xml

<Customer>
  <CustomerID>ALFKI</CustomerID>
  <CompanyName>Alfreds Futterkiste</CompanyName>
  <ContactName>Maria Anders</ContactName>
  <ContactTitle>Sales Representative</ContactTitle>
  <Address>Obere Str. 57</Address>
  <City>Berlin</City>
  <PostalCode>12209</PostalCode>
  <Country>Germany</Country>
  <Phone>030-0074321</Phone>
  <Fax>030-0076545</Fax>
  <Orders>
  <Order>
    <OrderID>10643</OrderID>
    <CustomerID>ALFKI</CustomerID>
    <EmployeeID>6</EmployeeID>
    <OrderDate>1997-08-25T00:00:00</OrderDate>
    <RequiredDate>1997-09-22T00:00:00</RequiredDate>
    <ShippedDate>1997-09-02T00:00:00</ShippedDate>
    <ShipVia>1</ShipVia>
    <Freight>29.4600</Freight>
    <ShipName>Alfreds Futterkiste</ShipName>
    <ShipAddress>Obere Str. 57</ShipAddress>
    <ShipCity>Berlin</ShipCity>
    <ShipPostalCode>12209</ShipPostalCode>
    <ShipCountry>Germany</ShipCountry>
    <Order_Details>
    <Order_Detail>
      <OrderID>10643</OrderID>
      <ProductID>28</ProductID>
      <UnitPrice>45.6000</UnitPrice>
      <Quantity>15</Quantity>
      <Discount>2.5000000e-001</Discount>
      <Product>
        <ProductID>28</ProductID>
        <ProductName>Rössle Sauerkraut</ProductName>
        <SupplierID>12</SupplierID>
        <CategoryID>7</CategoryID>
        <QuantityPerUnit>25 - 825 g cans</QuantityPerUnit>
        <UnitPrice>45.6000</UnitPrice>
        <UnitsInStock>26</UnitsInStock>
        <UnitsOnOrder>0</UnitsOnOrder>
        <ReorderLevel>0</ReorderLevel>
        <Discontinued>1</Discontinued>
      </Product>
    </Order_Detail>
    <Order_Detail>
      <OrderID>10643</OrderID>
      <ProductID>39</ProductID>
      <UnitPrice>18.0000</UnitPrice>
      <Quantity>21</Quantity>
      <Discount>2.5000000e-001</Discount>
      <Product>
        <ProductID>39</ProductID>
        <ProductName>Chartreuse verte</ProductName>
        <SupplierID>18</SupplierID>
        <CategoryID>1</CategoryID>
        <QuantityPerUnit>750 cc per bottle</QuantityPerUnit>
        <UnitPrice>18.0000</UnitPrice>
        <UnitsInStock>69</UnitsInStock>
        <UnitsOnOrder>0</UnitsOnOrder>
        <ReorderLevel>5</ReorderLevel>
        <Discontinued>0</Discontinued>
      </Product>
    </Order_Detail>
    </Order_Details>
  </Order>
  </Orders>
</Customer>

example1.cs

Serializer ser = new Serializer();
string path = string.Empty;
string xmlInputData = string.Empty;
string xmlOutputData = string.Empty;

// EXAMPLE 1
path = Directory.GetCurrentDirectory() + @"\Customer.xml";
xmlInputData = File.ReadAllText(path);

Customer customer = ser.Deserialize<Customer>(xmlInputData);
xmlOutputData = ser.Serialize<Customer>(customer)

example2.cs

Serializer ser = new Serializer();
string path = string.Empty;
string xmlInputData = string.Empty;
string xmlOutputData = string.Empty;

// EXAMPLE 2
path = Directory.GetCurrentDirectory() + @"\CustOrders.xml";
xmlInputData = File.ReadAllText(path);

Customer customer2 = ser.Deserialize<Customer>(xmlInputData);
xmlOutputData = ser.Serialize<Customer>(customer2);

Serializer.cs

using System;
using System.Collections;
using System.IO;
using System.Xml.Serialization;

namespace TestHarness
{
    public class Serializer
    {       
        public T Deserialize<T>(string input) where T : class
        {
            System.Xml.Serialization.XmlSerializer ser = new System.Xml.Serialization.XmlSerializer(typeof(T));

            using (StringReader sr = new StringReader(input))
            {
                return (T)ser.Deserialize(sr);
            }
        }

        public string Serialize<T>(T ObjectToSerialize)
        {
            XmlSerializer xmlSerializer = new XmlSerializer(ObjectToSerialize.GetType());

            using (StringWriter textWriter = new StringWriter())
            {
                xmlSerializer.Serialize(textWriter, ObjectToSerialize);
                return textWriter.ToString();
            }
        }
    }
}