protected override void ImplWrite (
TextWriter tw, IValueUnit source, IRepositorySerializationContext context )
{
if ( context.SerializeMetadata && context.Metadata != null )
if ( source == null )
source = context.Metadata as IValueUnit;
else
{
IValueUnit wrapperVu = new ValueUnit ();
wrapperVu.Add ( "$Metadata", context.Metadata );
wrapperVu.Add ( "$Data", source );
source = wrapperVu;
}
base.ImplWrite ( tw, source, context );
} // End of ImplWrite (...)
public async Task CreateOrMergeItemAsync(ShoppingListItem item)
{
ShoppingListItem itemOnList = await GetItemByNameAsync(item.OwnerId, item.Name);
// check if items could be merged
if (itemOnList != null && (ValueUnit.TryParse(itemOnList.Quantity, out ValueUnit onlistValue) && ValueUnit.TryParse(item.Quantity, out ValueUnit coreDataValue)))
{
// merge items
ValueUnit newValueUnit = ValueUnit.Add(onlistValue, coreDataValue);
itemOnList.Quantity = newValueUnit.ToString();
}
else
{
// create new item
_context.ShoppingListItems.Add(item);
}
await _context.SaveChangesAsync();
}