when i merge a data table with a typed dataset, one single field on a single row is DBNull sometimes

I have a strange problem sometimes when I try to merge a data table with a typed dataset

my data table is filled in with a stored procedure and when I checked the content of this table it is ok, everything is in there

straight after I merge it with my core typed dataset like this :

MyTypedDataSet.TheTable.Clear();
MyTypedDataSet.TheTable.Merge(MyDataTable);

and now if i check the table in the dataset everything is ok except only one single field on one single row which is DBNull, that makes no sense because the source data table contains the good integer vaue.

Thanks 开发者_StackOverflow社区a lot in advance guys :)