Writing/Saving XML Files - Page 2
       by kirupa  |  20 June 2007

In the previous page, you learned the basic steps required to write an XML file to disk. To review, you need to create an XmlDocument object, create an element to store some information, add that element to our XmlDocument object, and save the data from our XmlDocument to disk. All of this has only taken us four lines of code:

static void Main(string[] args)

{

XmlDocument xmlDoc = new XmlDocument();

 

XmlElement booksElement = xmlDoc.CreateElement("Books");

 

xmlDoc.AppendChild(booksElement);

xmlDoc.Save(@"C:\Users\Kirupa\Desktop\books.xml");

}

You are not finished with this tutorial yet, though! Right now we have only added our root element Books to our XML file. Let's populate our XML file with more data, and the following sections will help you to do just that.

Adding Nested Elements
Nested elements are, as the name implies, children of other elements. What we want is for our saved XML data to look like the following image you saw on the previous page:

Right now, we only have the Books part of the above document finished. Let's add our first book. Adding a nested element is exactly the same as adding any other element as you'll see. Add the following two lines of code directly after your booksElement declaration:

XmlElement bookElement = xmlDoc.CreateElement("Book");

booksElement.AppendChild(bookElement);

In the first line, you are creating a new XmlElement object called bookElement with the element name Book. In the next line, notice that you are adding your bookElement element as a child of booksElement. Earlier, you used AppendChild from your XmlDocument object, but this time, you are using AppendChild from your booksElement XmlElement instead.

If you run your application again by pressing F5 and looking at the XML file generated, you will see the following:

[ our Book node has now been added to our XML file ]

Our XML file is slowly starting to take shape. Let's populate our Book element with the title and author elements. Add the following lines of code directly after your booksElement.AppendChild(bookElement) line:

XmlElement titleElement = xmlDoc.CreateElement("title");

titleElement.InnerText = "Great Gatsby";

bookElement.AppendChild(titleElement);

 

XmlElement authorElement = xmlDoc.CreateElement("author");

authorElement.InnerText = "F. Scott Fitzgerald";

bookElement.AppendChild(authorElement);

The first lines of both sections should be familiar to you by now. You are creating an XmlElement with a given name that will be displayed in the XML file. In the code above, your titleElement and authorElement are responsible for storing the title and author elements respectively.

We have just named our elements, but these elements also need to store some data. To specify the data, you use your XmlElement object's InnerText property. Notice that the InnerText property, as its name implies, only accepts text values in the form of strings.

The final, third line is where you append the information to a parent element. Because we want the title and author elements to be children of our Book element, we use our bookElement's AppendChild method.

All of your code right now should look like the following:

static void Main(string[] args)

{

XmlDocument xmlDoc = new XmlDocument();

 

XmlElement booksElement = xmlDoc.CreateElement("Books");

 

XmlElement bookElement = xmlDoc.CreateElement("Book");

booksElement.AppendChild(bookElement);

 

XmlElement titleElement = xmlDoc.CreateElement("title");

titleElement.InnerText = "Great Gatsby";

bookElement.AppendChild(titleElement);

 

XmlElement authorElement = xmlDoc.CreateElement("author");

authorElement.InnerText = "F. Scott Fitzgerald";

bookElement.AppendChild(authorElement);

 

xmlDoc.AppendChild(booksElement);

xmlDoc.Save(@"C:\Users\Kirupa\Desktop\books.xml");

}

If you run your application and look at your XML file again, you will now see the following:

[ our Book node is almost complete with our title and author information ]

You should now see both the nodes for title and author, and we are almost done with our first book. I mention almost, because we still need to add the missing ISBN attribute information. Let's look at how to do that on the next page.

Onwards to the next page!

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