Serialize XML same tag twice

Use an array:

public class Test{    [XmlElement("HeaderText")]    public string[] HeaderText { get; set; }}

and then:

var doc = new Test{    HeaderText = new[] { "AAA", "BBB" }};var xml = new XmlSerializer(typeof(Test));using (var fs = new FileStream("test.xml", FileMode.Create)){    xml.Serialize(fs, doc);}

Also works with List<string>.

UPDATE:

With complex objects you define a model:

public class Header{    public string Tag { get; set; }}

and then you have a collection of this model:

public class Test{    [XmlElement("HeaderText")]    public Header[] HeaderText { get; set; }}

and then you serialize:

var doc = new Test{    HeaderText = new[]     {         new Header { Tag = "AAA" },         new Header { Tag = "BBB" }    }};var xml = new XmlSerializer(typeof(Test));using (var fs = new FileStream("test.xml", FileMode.Create)){    xml.Serialize(fs, doc);}

You could tell the serializer to ignore your current properties, and add a new one for the purpose of serialization:

public class Test{    [XmlIgnore]    public String Header1 { get; set; }    [XmlIgnore]    public String Header2 { get; set; }    [XmlElement("HeaderText")]    public String[] HeaderText    {        get{  return new[]{Header1,Header2};   }        set{  if(value.Length == 2) { Header1 = value[0]; Header2 = value[1];} }    }}

Live example: http://rextester.com/YVEF64085