Programmatically add a row to a repeating table using an XmlWriter object

1. Add the following code to the Clicked event handler of the button:
   
   C#
   string myNamespace = NamespaceManager.LookupNamespace("my");
using (XmlWriter writer = MainDataSource.CreateNavigator().SelectSingleNode("/my:myFields/my:group1", NamespaceManager).AppendChild())
{writer.WriteStartElement("group2", myNamespace);writer.WriteElementString("field1", myNamespace, "Cell 1");writer.WriteElementString("field2", myNamespace, "Cell 2");writer.WriteElementString("field3", myNamespace, "Cell 3");writer.WriteEndElement();writer.Close();
}
   
   Visual Basic
   Dim myNamespace As String = NamespaceManager.LookupNamespace("my")
Using writer As XmlWriter = MainDataSource.CreateNavigator().SelectSingleNode( _"/my:myFields/my:group1", NamespaceManager).AppendChild()writer.WriteStartElement("group2", myNamespace)writer.WriteElementString("field1", myNamespace, "Cell 1")writer.WriteElementString("field2", myNamespace, "Cell 2")writer.WriteElementString("field3", myNamespace, "Cell 3")writer.WriteEndElement()writer.Close()
End Using

2. Save, build, and test your work.

Article taken from:

http://www.bizsupportonline.net/infopath2007/programmatically-add-row-repeating-table-xmlwriter.htm