BCP ignore the trigger, what can I do?

Question

When I use BCP data into database, the trigger is not fired. What should I do to make the trigger useful? Can I merely update the data without changing values?

     try
        {
            //get all data
            string strConn = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=" + excelFile + ";" + "Extended Properties=Excel 8.0;";
            OleDbConnection conn = new OleDbConnection(strConn);
            conn.Open();
            string strExcel = "";
            strExcel = string.Format("select * from [{0}$] where xh<>''", sheetName);
            OleDbDataAdapter oda = new OleDbDataAdapter(strExcel, strConn);
            oda.Fill(ds, sheetName);

            //BCP data
            using (SqlBulkCopy bcp = new SqlBulkCopy(connectionString))
            {
                bcp.SqlRowsCopied += new SqlRowsCopiedEventHandler(bcp_SqlRowsCopied);
                bcp.BatchSize = 100;//the speed of import
                bcp.NotifyAfter = 100;
                bcp.DestinationTableName = sheetName;//target table
                bcp.WriteToServer(ds.Tables[0]);
            }
        }
   catch (Exception ex)
        {
            System.Windows.Forms.MessageBox.Show(ex.Message);
        }

The trigger is following.

create trigger getAge
on tablename
for insert ,update
as
if update(birthday)
update tablename set age=DateDiff(year,birthday,getdate())
go

Answer 1

Check this MSDN article: http://msdn.microsoft.com/en-us/library/ms187640.aspx

Using bcp, triggers are disabled by default. To enable it, use the following argument:

-h "FIRE_TRIGGERS"

When working with the SqlBulkCopy class provided by .NET, use the SqlBulkCopyOptions enum to enable trigger.