I wrote this helper class because sometimes I have some projects that need to use XML file format to save some states or configurations and to retrieve the configurations back. I like to work with XML file as the content is easy to be edited and human readable by using any code editor application. So, this is my own version of simple XML helper class to ease my work with XML data serialization and deserialization.
Helper class source code
XmlHelper.cs // Also available on my Gist too.
using System;
using System.IO;
using System.Text;
using System.Xml;
using System.Xml.Serialization;
namespace HeiswayiNrird.Utility.Common
{
public static class XmlHelper
{
/// <summary>
/// Serialize a serializable object to XML string.
/// </summary>
/// <typeparam name="T">Type of object</typeparam>
/// <param name="xmlObject">Type of object</param>
/// <param name="useNamespaces">Use of XML namespaces</param>
/// <returns>XML string</returns>
public static string SerializeToXmlString<T>(T xmlObject, bool useNamespaces = true)
{
XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
MemoryStream memoryStream = new MemoryStream();
XmlTextWriter xmlTextWriter = new XmlTextWriter(memoryStream, Encoding.UTF8);
xmlTextWriter.Formatting = Formatting.Indented;
if (useNamespaces)
{
XmlSerializerNamespaces xmlSerializerNamespaces = new XmlSerializerNamespaces();
xmlSerializerNamespaces.Add("", "");
xmlSerializer.Serialize(xmlTextWriter, xmlObject, xmlSerializerNamespaces);
}
else
xmlSerializer.Serialize(xmlTextWriter, xmlObject);
string output = Encoding.UTF8.GetString(memoryStream.ToArray());
string _byteOrderMarkUtf8 = Encoding.UTF8.GetString(Encoding.UTF8.GetPreamble());
if (output.StartsWith(_byteOrderMarkUtf8))
{
output = output.Remove(0, _byteOrderMarkUtf8.Length);
}
return output;
}
/// <summary>
/// Serialize a serializable object to XML string and create a XML file.
/// </summary>
/// <typeparam name="T">Type of object</typeparam>
/// <param name="xmlObject">Type of object</param>
/// <param name="filename">XML filename with .XML extension</param>
/// <param name="useNamespaces">Use of XML namespaces</param>
public static void SerializeToXmlFile<T>(T xmlObject, string filename, bool useNamespaces = true)
{
try
{
File.WriteAllText(filename, SerializeToXmlString<T>(xmlObject, useNamespaces));
}
catch
{
throw new Exception();
}
}
/// <summary>
/// Deserialize XML string to an object.
/// </summary>
/// <typeparam name="T">Type of object</typeparam>
/// <param name="xml">XML string</param>
/// <returns>XML-deserialized object</returns>
public static T DeserializeFromXmlString<T>(string xml) where T : new()
{
T xmlObject = new T();
XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
StringReader stringReader = new StringReader(xml);
xmlObject = (T)xmlSerializer.Deserialize(stringReader);
return xmlObject;
}
/// <summary>
/// Deserialize XML string from XML file to an object.
/// </summary>
/// <typeparam name="T">Type of object</typeparam>
/// <param name="filename">XML filename with .XML extension</param>
/// <returns>XML-deserialized object</returns>
public static T DeserializeFromXmlFile<T>(string filename) where T : new()
{
if (!File.Exists(filename))
{
throw new FileNotFoundException();
}
return DeserializeFromXmlString<T>(File.ReadAllText(filename));
}
}
}
Usage examples
You need to create a serializable object class before you can use. This can be any of the model class if you want. For example, I have this object class to use and as you can see I applied XML attributes to the object properties in case I want to rename them to different names in my XML file:
using System.Collections.Generic;
using System.Xml.Serialization;
namespace XmlHelperConsoleApp
{
[XmlRoot("MyCompanyEmployees2016")]
public class CompanyEmployee
{
public List<Employee> EmployeeList { get; set; }
}
public class Employee
{
[XmlAttribute("Name")]
public string Name { get; set; }
[XmlAttribute("Age")]
public int Age { get; set; }
[XmlAttribute("Position")]
public string Position { get; set; }
[XmlAttribute("Department")]
public Department Department { get; set; }
}
public enum Department
{
Technical,
Marketing,
Support
}
}
Serialize object to XML string
Here’s the example code for serializing the object to XML string:
using HeiswayiNrird.Utility.Common;
using System;
using System.Collections.Generic;
using System.Linq;
namespace XmlHelperConsoleApp
{
internal class Program
{
private static void Main(string[] args)
{
var employee1 = new Employee()
{
Name = "John Cornor",
Age = 40,
Position = "Technical Engineer",
Department = Department.Technical
};
var employee2 = new Employee()
{
Name = "James Bond",
Age = 44,
Position = "Marketing Manager",
Department = Department.Marketing
};
var employee3 = new Employee()
{
Name = "Jason Bourne",
Age = 40,
Position = "Field Application Engineer",
Department = Department.Technical
};
var employeeList = new List<Employee>() { employee1, employee2, employee3 };
var companyEmployee = new CompanyEmployee()
{
EmployeeList = employeeList
};
string xml = XmlHelper.SerializeToXmlString(companyEmployee);
Console.WriteLine(xml);
Console.ReadKey();
}
}
}
Output
The code above will output a XML-formatted string like this:
<?xml version="1.0" encoding="utf-8"?>
<MyCompanyEmployees2016>
<EmployeeList>
<Employee Name="John Cornor" Age="40" Position="Technical Engineer" Department="Technical" />
<Employee Name="James Bond" Age="44" Position="Marketing Manager" Department="Marketing" />
<Employee Name="Jason Bourne" Age="40" Position="Field Application Engineer" Department="Technical" />
</EmployeeList>
</MyCompanyEmployees2016>
Deserialize XML string to object
Now, if you want to get specific value from the XML string, we need to deserialize it and retrieve our desired value. Here’s the example code how to do it:
using HeiswayiNrird.Utility.Common;
using System;
using System.Collections.Generic;
using System.Linq;
namespace XmlHelperConsoleApp
{
internal class Program
{
private static void Main(string[] args)
{
// string xml = <...XML-formatted string...>
var obj = XmlHelper.DeserializeFromXmlString<CompanyEmployee>(xml);
// Get list of employee names from Technical department
var getTechnicalDept = obj.EmployeeList.Where(x => x.Department == Department.Technical).ToList();
foreach (var employee in getTechnicalDept)
Console.WriteLine(employee.Name);
Console.ReadKey();
}
}
}
Output
The code above will output something like this:
John Cornor
Jason Bourne
Resolving Byte Order Mark (BOM) bug
“Data at the root level is invalid. Line 1, position 1.”
In the beginning of writing this helper class, I have encountered with this kind of exception message when I tried to deserialize the XML string. After I did some researches on Google, I found a blog that explained the root cause and detailed solution. That bug is known as BOM, a Unicode character used to signal the endianness (byte order) of a text file or stream.
Below is the code snippet fix that I have applied inside serializing method before outputting to XML string in order to resolve the issue:
string _byteOrderMarkUtf8 = Encoding.UTF8.GetString(Encoding.UTF8.GetPreamble());
if (xml.StartsWith(_byteOrderMarkUtf8))
{
xml = xml.Remove(0, _byteOrderMarkUtf8.Length);
}