public void WriteXml(XmlWriter writer, object value, XmlSerializationContext context)
{
if (context.Member.MappingType != XmlMappingType.Element)
{
throw new XmlSerializationException($"XML mapping of \"{context.ValueType}\" must be Element.");
}
var collectionItem = GetCollectionItem(context);
if (collectionItem == null)
{
throw new XmlSerializationException(
$"XML contract of \"{context.ValueType}\" must contains collection item");
}
Type lastItemType = null;
XmlTypeContext typeContext = null;
foreach (var item in (IEnumerable)value)
{
if (item == null)
{
context.WriteNull(writer, collectionItem.ValueType, collectionItem);
}
else
{
var member = (XmlMember)collectionItem;
var shouldWriteTypeName = context.TryResolveValueType(item, ref member, out Type itemType);
if (itemType != lastItemType)
{
typeContext = context.Settings.GetTypeContext(itemType);
lastItemType = itemType;
}
writer.WriteStartElement(member.Name);
if (shouldWriteTypeName)
{
context.WriteTypeName(writer, lastItemType);
}
context.WriteXml(writer, item, member, typeContext);
writer.WriteEndElement();
}
}
}
