thx for your reply!
[have multi same value] i mean same string appeared multi times in the collection<string> collection, like Collection<string> collection=new Collection(){"1","2","3","1","2"};
and i followed your guid ,tested it , below
ProductCollection productCollectionToSave= new ProductCollection();
try
{
for (int i=0;i<6;i++)
{
ProductEntity productEntity = new ProductEntity(Collection[i]);
if (!productEntity.IsNew)
{
productEntity.TempStock = productEntity.TempStock -2;
collectionToSave.Add(productEntity);
}
}
trans.Add(productCollectionToSave);
productCollectionToSave.SaveMulti();
however, it also turn out [time out] error,
is it because the sample product is appeared in the transaction multi times,so that it may be in chaos?