public async Task Handle(CreateCategory message)
{
try
{
var item = await repository.Get(message.Id.ToString());
if (item != null)
{
throw new Exception($"Category with id: {message.Id} already exist");
}
}
catch (AggregateNotFoundException)
{
// That is fine that id not used
}
var category = CategorySource.Create(message.Id, message.ParentId, message.Name, message.Color, message.Visible);
await repository.Save(category);
}