Create an XML File or XmlDocument Directly from a StringBuilder

An earlier DevX tip, "Create a New XML File Using XmlDocument," showed how to create a new XmlDocument, populate it, and save the results to a file. This tip uses the same XML example, but builds the document with a StringBuilder instead, which is simpler than working directly with the System.Xml.XmlDocument class.

Suppose you want to build this XML:

<?xml version="1.0" encoding="utf-8"?>
<CategoryList>
  <Category ID="01">
    <MainCategory>XML</MainCategory>
    <Description>This is a list of my XML articles.</Description>
    <Active>true</Active>
  </Category>
</CategoryList>

The following method shows how to build the preceding document with a StringBuilder. The following code gets a StringBuilder containing the minimal XML, appends strings containing the elements, loads an XmlDocument instance from the StringBuilder contents, and returns the populated XmlDocument object:

public XmlDocument BuildXmlDocument()
{
   StringBuilder Document = CreateBaseStringBuilder(); // create a generic XML string
   //declare the root.
   Document.AppendLine("<CategoryList>");

   // declare child node.
   Document.AppendLine("<Category ID=\"01\">"); //We could tab indention

   // add child node's child node
   Document.AppendLine("<MainCategory>XML</MainCategory>");

   // add another child node
   Document.AppendLine("<Description>This is a list of my XML articles.</Description>");

   // and another
   Document.AppendLine("<Active>true</Active>");

   // close the Category node.
   Document.AppendLine("</Category>");

   // close the root node
   Document.AppendLine("</CategoryList>");

   // now read the contents into an XmlDocument
   try
   {
      // Create the new Instance.
      XmlDocument XMLDocument = new XmlDocument();

      // Add the content
      XMLDocument.LoadXml(Document.ToString());

      // return it.
      return (XMLDocument);
   }
   catch(Exception ex)
   {
      // in case of failure return null
      return (null);
   }
}


// This function creates a new instance of System.Text.StringBuilder, 
// adds a Basic XmlDocumentDeclaration, 
// and returns the new StringBuilder.
private StringBuilder CreateBaseStringBuilder()
{
   StringBuilder BaseDocument = new StringBuilder();
   BaseDocument.AppendLine("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
   return (BaseDocument);
}

Note that you'd need to call the returned XmlDocument's Save method from the calling function.