/// <summary>
/// Creates an XML document from a row tree and writes it to a stream using UTF-8 encoding.
/// </summary>
// If we need to start generating XML on the fly for HTTP responses, it may make sense to create an overload of this method that takes an HttpResponse
// object instead of a stream. This new overload would use the HttpResponse.Output property to obtain a TextWriter and then create the XmlWriter on top of
// that instead of a stream. The advantage of this approach is that the encoding of the XML would then be determined by ASP.NET, which takes into account
// any request headers the client may have sent that pertain to the desired encoding of the response.
public static void CreateXmlDocument(MergeRowTree rowTree, MergeFieldNameTree fieldNameTree, Stream destinationStream)
{
using (var writer = XmlWriter.Create(destinationStream)) {
writer.WriteStartDocument();
writeRowTreeXmlElement(rowTree, fieldNameTree, writer);
writer.WriteEndDocument();
}
}
private static void writeRowTreeXmlElement(MergeRowTree rowTree, MergeFieldNameTree fieldNameTree, XmlWriter writer)
{
writer.WriteStartElement(rowTree.NodeName);
foreach (var row in rowTree.Rows)
{
writer.WriteStartElement(rowTree.XmlRowElementName);
foreach (var fieldName in fieldNameTree.FieldNames)
{
var mergeValue = row.Values.SingleOrDefault(i => i.Name == fieldName);
if (mergeValue == null)
{
// Use ApplicationException instead of MailMergingException because the field names can easily be validated before this method is called.
throw new ApplicationException("Merge field " + fieldName + " is invalid.");
}
writer.WriteStartElement(mergeValue.Name);
if (mergeValue is MergeValue <string> )
{
writer.WriteValue((mergeValue as MergeValue <string>).Evaluate(false));
}
else
{
// Use ApplicationException instead of MailMergingException because the field names can easily be validated before this method is called.
throw new ApplicationException("Merge field " + mergeValue.Name + " evaluates to an unsupported type.");
}
writer.WriteEndElement();
}
foreach (var childNameAndFieldNameTree in fieldNameTree.ChildNamesAndChildren)
{
var childRowTree = row.Children.SingleOrDefault(i => i.NodeName == childNameAndFieldNameTree.Item1);
if (childRowTree == null)
{
// Use ApplicationException instead of MailMergingException because the child names can easily be validated before this method is called.
throw new ApplicationException("Child " + childNameAndFieldNameTree.Item1 + " is invalid.");
}
writeRowTreeXmlElement(childRowTree, childNameAndFieldNameTree.Item2, writer);
}
writer.WriteEndElement();
}
writer.WriteEndElement();
}