Exporting Data: Creating XML Files using C#

Posted on August 19, 2008. Filed under: .NET, ASP.NET, C#, programming, XML, XSD | Tags: , , , , |

When you want to export data, you can choose formats such as XML or csv for the data files. The XML format is more widely used for its flexibility and is desirable by many systems to be able to process the data. This article explains how to create xml files from C# classes.

Situation: Where would you use it:
– When you have to export data from one system to another system on a different platform
– When you have to setup scheduled jobs to export data
– When you want to keep a backup of key data on a regular basis. Though the database will give (better) alternatives, this technique will help you in shared hosting environments where you may want to keep a good backup of users who have signed up on your site, on a daily basis, for example.

This article touches the following technological aspects:
– C# class library
– Creating XML Schema (XSD)
– Generating C# Class file from XSD
– Generating XML files from C# object using XmlSerializer

Generate xml to export data

Figure 1: Generate xml to export data

Example:
Suppose you have the following data which need to be exported in the form of XML files.
Customers:
CustomerID
CompanyName
ContactName
Address
City
PostalCode
Country
Phone
Fax

Each customer may have one-to-many Orders.

Orders:
OrderID
CustomerID
OrderDate
RequiredDate
ShippedDate
ShipAddress
ShipCity
ShipPostalCode
ShipCountry

To export this data on a daily basis, you would create XML files in the following format:

<Customers>
<CustomerID />
<CompanyName />

<Orders>
<OrderID />
<OrderDate />

</Orders>
<Orders />
<Orders />

</Customers>
<Customers />
<Customers />

Here are the steps to create it:

1) Create new project in Visual Studio

Creating New Project

Figure: Creating New Project

2) Add a class library to the project

Adding a class library to the solution

Figure: Adding a class library to the solution

3) Add a schema (.xsd) file to the class library project

Adding schema file to the project

Figure: Adding schema file to the project

4) Add schema elements. There are different ways in which you can add elements. One simple way is to drag and drop the database tables from the server explorer into the .xsd’s design area (when MySchema.xsd is opened with XML Schema Editor).

For this exercise, add Customers and Orders tables from the Northwind database from the server explorer.

The completed schema will look like this in the designer.

Customers and Orders schema

Figure: Customers and Orders schema

See the project source code to view the XSD code (ie with XML tags)

5) Generate the C# Class from xsd

At the VS Command prompt, enter xsd /c MySchema.xsd. This will create MySchema.cs. Rename it to MySchemaClass.cs, add it to the MyDataLayer class library project, update the namespace of MySchemaClass.cs

If your schema’s top element is named ExportData, (<xs:element name=ExportData>) MyDataLayer class will have a class named ExportData (public partial class ExportData).

(I’ve also updated the OrderDate datatype to be string in the generated class, to produce a formatted output in the XML)

6) Create the object from ExportData class and fill the object’s properties with data (from Database or from any other source).

eg:

private ExportData _exportXmlData = new ExportData();
(See the source code for full details).

7) Use the XmlSerializer to create XML files

eg:

FileStream fs = null;

try
{
XmlSerializer serializer = new XmlSerializer(typeof(ExportData));

fs = new FileStream(_fileName, FileMode.Create, FileAccess.Write);

serializer.Serialize(fs, _exportXmlData);

}

catch
{
throw;

}
finally

{

if (fs != null)
{
fs.Close();

}
}

(See the source code for full details).

8 ) Run the project. It will create the XML files containing data, which can be exported (via ftp or saved directly to a shared drive).

A typical customer data in the XML file produced by this example will have the following format:

<Customers>

<CustomerID>2</CustomerID>

<CompanyName>Company Name 2</CompanyName>

<ContactName>Contact Name 2</ContactName>

<City>Dallas 2</City>

<Orders>

<OrderID>2000</OrderID>

<OrderDate>Tuesday, August 19, 2008</OrderDate>

<RequiredDate>2008-08-21T14:33:31.8125-05:00</RequiredDate>

<ShipName>UPS 2</ShipName>

</Orders>

<Orders>

<OrderID>2001</OrderID>

<OrderDate>Tuesday, August 19, 2008</OrderDate>

<RequiredDate>2008-08-21T14:33:31.8125-05:00</RequiredDate>

<ShipName>UPS 2</ShipName>

</Orders>

</Customers>

Source Codes:

Please click here to get the source code link. (I hate spam as much as you do and your email id will never be given to others)

Feel free to comment your thoughts / questions / suggestions below.

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28 Responses to “Exporting Data: Creating XML Files using C#”

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Really nice article ! Very informative and all the figures and examples are extremely helpful ! Please write similar articles on other C# and ASP.NET topics .

@Chhaya, Thank you very much for the comment!

What are some of the .NET technologies & features your projects use?

using this m able to generate xml but how can i map these xml tags with tally xml tags please help me

@pradnya, Your schema (xsd) should match the schema required by tally. Then the generated xml file will contain the xml tags mapping to tally xml tags. If you have a sample tally xml file, open it in visual studio, go to xml menu and click generate schema. When you use this schema to generate c# class, populate data and generate xml files, its tags should match tally xml tags. Hope this helps.

Excellent article it really helps.
But I have one question if you need to add how would I go about specifying that in the xsd or the class?

@Pratheek, You can add any new elements similar to the existing elements in the xsd. If you update the xsd, you should regenerate the class. Pls let me know if you have further questions.

Thank you very much for the sample.
I actually already have my own code doing pretty much the same thing, just slightly different than yours.
I was running into a small issue and thats why i landed on your article =)
My code is very similar to yours except when it comes to step 7, instead of using a serializer,
i am doing myObjectName.GetXml() and my schema is attached to a namespace. My code works perfect except
I can only get the root element to be prefixed with what I have specified
as the prefix, the children elements are not prefixed.
I also tried your sample, since i needed the output xml to be in memory, i changed your filestream to a string writer.
I also added an xmlSerializerNamespace object to specify the namespace and prefix.
The outputted xml still does not have the correct prefix. If you dont mind, I have two questions.

1. would you happen to have any idea how to add prefix to the child elements using my original approach?
2. is there a reason why you chose xmlSerializer instead of just simple call the getXml method?

Thanks again, look forward to hearing from you.

@mango, Thank you for the comment and great questions. When you’ve a dataset, you can use GetXml to keep it simple. When you have a complex schema and lots of business logic, it helps to create a class which can be populated considering different rules, and then use XmlSerializer. About using the prefixes, please see http://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlserializernamespaces.aspx. The sample given at that link produces the xml with prefixes to child elements. Hope you find the solution you are looking for and please drop a line here when you do :)

Thanks for the code. I appreciate it. I am currently working on a similar project. There is a main database from which data is extracted in xml file, and then using that xml file updated in a secondary replica database. I am now able to generate an xml file with the related records. Could you please let me know how should i go ahead and use the xml to update the secondary database(Ms. Access). It has the same tables and columns as the primary one. I tried generating dataset from the xml file and then using adapters, i tried updating the data tables. But it gave error saying valid insert command required.

My approach can be wrong. I would appreciate if you let me know the correct approach.
Thanks in advance.

Thanks vinbhat for the explanation. As mentioned, i did try using your sample + xmlSerializerNamespace and still was not appending the prefix. I think i might end up transforming it, which doesnt really make sense, there must be a way… Thanks again for your response, off to more research =)

Thanks for this article! :)

tahnks for the comment. its very good. now i understand how to use xsd to create xml with exported data.

Thank you for this article, very good. I am currently working on a similar project but I have to create only one XML file with data from different classes.

What would be the correct code with the XmlSerializer. ?
What is

This is one of the best methods and never imagined something like this existed also…..
BUT
I also have an issue like one other anonymous user. it causes “q1:” to go in front of every single element, including the root.

I am not sure if i am doing anything incorrect or is it like this only…Please respond

@Tom, XmlSerializer produces one XML file for the given class. If you want create one XML file from different classes, I think you have to create a schema and generate a class. Fill that class from the data from your different classes. Then use XmlSerializer on this single class.

@Pooja, I think, the prefix comes from the namespace. (http://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlserializernamespaces.aspx). You may update your schema (XSD) and retry. The sample project included in the source code doesn’t produce any prefixes in the generated XML files. Another less efficient way is to use a stream reader and replace the unwanted characters after the xml file is generated.

it was best. but what will be the code for reading such files

@venus, There are different ways to read such files. Here’s one of them:
Using System.Xml;

XmlDocument doc = new XmlDocument();
doc.Load(@”C:\myfolder\myfile.xml”);
XmlNodeReader reader1 = new XmlNodeReader(doc);

Please see http://support.microsoft.com/kb/307548 for details and other examples.

I am lookimg into your example and find it very interesting, only problem is that I cannot get to the code sample for some reason…

HI vinbhat

My name is Abhijit.
I am intrested in reading the Data of an XML and putting in it the SQL DataBase( for Interoperability). I have tried using the DataSets ReadXML method to achive the same
But its throwing an exception “Cannot add constraint to DataTable ‘xyz’ which is a child table in two nested relations.”
This was a known issue with .NET.

I want to read the XML Data in Custom Objects.
Can you help me with the same.

Hi Thanks for this article. It really helps a lot. Please continue to write.

Hi,
This is a nice and helpful article. I was wondering if you can compare two XML files and find out if the data is different. For example in the example given, if I create XML file everymonth and find that there is change from previous month to this month for a customer, i would like to create file for only the changed customer. How can we do it? Is there an XML cpmpare functionality?
Thanks

Vijay S

Thanks for the article.
The example you have given is very general, and I do not find any difficulty in generating this type of XML file myself.
My requirement is a little different one.
I would be pleased to know; How I can generate an XML file similar to the following:

Any help would be appriciated

Thanks

<visitInformation

Thankx for the Article but i want to Import this
xml to tally…can u help me in that case to connect to tally database.

Thanks it was very helpful for me.
Thanks in million vinbhat.

Hi……its really a nice article!i have followed all steps and got proper output but i want to export this
XML document to tally server…as i have made xml
which is matching to tally sample xml.can u plz
help me in this……

@Reshma, I haven’t used & dont know much abt Tally. But I found this info (which you might already have) – Tally allows users to Import data from other software’s as well as Export data from Tally to other software’s. Tally allows users to Import and Export in ASCII, SDF and XML formats. XML is now the most widely used format of exporting data in the world. Visit their page: http://www.antraweb.com/TechnologyAdvantage.htm for screen shots & more info.

@All, HELP!! I’m not finding time to reply to some of the questions above. If anyone knows the answers, please post a comment here which benefits all. It is much appreciated. Thank you!


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    My stuff about .NET, C#, ASP.NET, AJAX, Visual Studio, SQL Server, XML, Web Services, WCF, WPF, WF, CRM, etc.

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