Get the line number on which the request to database ended with an error

I use this code to send sql request:

 SqlBulkCopy bulkCopy = new SqlBulkCopy(Connection);

                foreach (DataColumn column in dt.Columns)
                {
                    bulkCopy.ColumnMappings.Add(column.ColumnName, column.ColumnName);
                }
                bulkCopy.DestinationTableName = "nsi." + classifierData.Info.TableName;
                bulkCopy.WriteToServer(dt);

and get an exception : "Received an invalid column length from the bcp client for colid". How can I find an row number with error data?

I've tried to use this, but it does'nt work (values are always the same):

 FieldInfo currentRow = typeof(SqlBulkCopy).GetField("_currentRowLength", BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);
                    var currentRowNumber = currentRow.GetValue(bulkCopy);

                    FieldInfo _rowsCopiedField = typeof(SqlBulkCopy).GetField("_rowsCopied", BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);
                    var currentRowN = _rowsCopiedField.GetValue(bulkCopy);