Introduction
There is a general
requirement in many projects to parse XML to an object and vice versa. Instead
of using inefficient and error prone method of manual XML parsing, .NET object
serialization/deserialization functionality can be used to achieve similar
result in a more efficient and elegant manner. This approach is very generic
and will work with all types of XML.
Approach
System.Runtime.Serialization
provides methods for serializing and de-serializing XMLs.
DataContractSerializer
method of System.Runtime.Serialization
namespace can be used to achieve functionality of -
- XML
to object conversion (XML Parsing [De-Serialization])
- Object to XML conversion (Object Serialization)
- Apart from this, Generics feature of C# has been utilized to make the methods generic and independent of object types. It also enhances type-safety of the code. Actual type needs to be specified only when method is called.
- The
method for ‘Serialization’ accepts type of data to serialize as a
parameter ‘T’. This makes the method generic in a sense that it can accept
object of any type for serialization and we don’t have to define that at
time of method declaration.
- The method for ‘De-Serialization’ returns de-serialized data. The return type has been specified as generic ‘T’. This makes the method generic in a sense that it can de-serialize and return object of any type.
Implementation
1. Class
declaration
1.1. Create a static class
named ‘XmlParserDeparser’.
1.2. Reason for making
this class static is that this class acts as a utility class and there will be
no need to create instance of this class to access its helper methods.
1.3. Add following
namespace in the class file –
1.3.1. using System;
1.3.2. using
System.Collections.Generic;
1.3.3. using System.IO;
1.3.4. using
System.Runtime.Serialization;
1.3.5. using System.Text;
2.
XML to object conversion (XML
parsing/de-serialization)
2.1. To achieve this
conversion, DataContractSerializer
method of System.Runtime.Serialization
will be used.
2.2. Declare a static method
with name XmlToObject<T>.
2.3. Here ‘T’ will be type of the data object to
create after parsing XML using de-serialization techniques.
2.4. This method will
return object created from XML.
2.5. It will take two
input parameters -
·
XML
as string
·
Known
types to include in the serializer (can be null too)
2.6. Complete code for the
method is presented below –
/// <summary>
/// Deserializes the specified XML string.
/// </summary>
/// <typeparam name="T">The type of the data to deserialise to.</typeparam>
/// <param name="xml">The XML string representing the data to
deserialise.</param>
/// <param name="knownTypes">The known types to
include in the serializer.</param>
/// <returns>The deserialised data in object form.</returns>
public static T XmlToObject<T>(string xml, IEnumerable<Type> knownTypes)
{
using (var stream = new MemoryStream(Encoding.Unicode.GetBytes(xml)))
{
var
serializer = new DataContractSerializer(typeof(T), knownTypes);
T theObject =
(T)serializer.ReadObject(stream);
return
theObject;
}
}
2.7. Here a memory stream
is created using XML as input.
2.8. An instance of System.Runtime.Serialization.DataContractSerializer
is created specifying type ‘T’ and enumeration of knownTypes as input. Latter is optional though (can be null).
2.9. Now the object of DataContractSerializer reads the XML
and creates a generic object.
2.10.
This
object is cast to type ‘T’ and then returned.
2.11.
We
can also create over-load of this method with only one parameter i.e. ‘XML as
string’.
2.12.
This
method will internally call the above method with ‘knownTypes’ passed as null.
2.13.
The
signature for this method will be as follows –
///
<summary>
/// Deserializes the
specified XML string.
/// </summary>
/// <typeparam name="T">The type of the data to deserialise to</typeparam>
/// <param name="xml">The XML string representing the data to deserialise</param>
/// <returns>The
deserialised data in object form</returns>
public static T
XmlToObject<T>(string xml)
{
return XmlToObject<T>(xml, null);
}
3. Object
to XML conversion (Object serialization)
3.1. To achieve this
conversion, DataContractSerializer
method of System.Runtime.Serialization
will be used.
3.2. Declare a static method
with name ObjectlToXml<T>.
3.3. Here ‘T’ will be type of the data object to convert
to XML using serialization techniques.
3.4. This method will
return XML as string.
3.5. It will take two
input parameters -
·
Type
of object to convert to XML
·
Known
types to include in the serializer (can be null too)
3.6. Complete code for the
method is presented below –
/// <summary>
/// Serializes the specified input data, of type T, to XML string.
/// </summary>
/// <typeparam name="T">The type of the data to serialise.</typeparam>
/// <param name="data">The data to serialise.</param>
/// <param name="knownTypes">The known types to
include in the serializer.</param>
/// <returns>The data as an XML string.</returns>
public static string
ObjectToXml<T>(T data, IEnumerable<Type> knownTypes)
{
using (var memoryStream = new
MemoryStream())
{
var
serializer = new DataContractSerializer(typeof(T), knownTypes);
serializer.WriteObject(memoryStream,
data);
memoryStream.Seek(0, SeekOrigin.Begin);
var
reader = new StreamReader(memoryStream);
string
content = reader.ReadToEnd();
return content;
}
}
3.7. Here a memory stream
is created first.
3.8. An instance of System.Runtime.Serialization.DataContractSerializer
is created specifying type ‘T’ and enumeration of knownTypes as input. Latter
is optional though (can be null).
3.9. Now the object of DataContractSerializer reads the object
data and writes the output (XML) into memory stream.
3.10.
This
memory stream is then read by a StreamReader
object till end and converted to string which is returned by method.
3.11.
We
can also create over-load of this method with only one parameter i.e. ‘Type of object to convert to XML’.
3.12.
This
method will internally call the above method with ‘knownTypes’ passed as null.
3.13.
The
signature for this method will be as follows –
/// <summary>
/// Serializes the
specified input data, of type T, to XML string.
/// </summary>
/// <typeparam name="T">The type of the data to serialise.</typeparam>
/// <param name="data">The data to serialise.</param>
/// <returns>The data as
an XML string.</returns>
public static string ObjectToXml<T>(T data)
{
return ObjectToXml(data, null);
}
Advantages
- The
advantage of using this approach is that you are able to perform XML
parsing very easily without writing custom parsing code.
- Similarly you are able to easily convert an object to XML without need of any custom code.
- This
code is generic and will work for all types of XML and objects. We just
need to ensure to specify proper XML and object type (T).
