A Problem About Inserting A New Row With SqlDataAdapter

Since my select command involves multiple tables, I manually write the insert command, proplating the SqlParameters as follows:

string insCmdText =
                "INSERT INTO itcac_alan.COURSE " +
                " ([COURSE_ID], [COURSE_NAME], [COURSE_NO], [BEGIN_DATE], [END_DATE], [CREATER]) " +
                " VALUES(@COURSE_ID, @COURSE_NAME, @COURSE_NO, @BEGIN_DATE, @END_DATE, @CREATER)";

            SqlCommand insCmd = new SqlCommand(insCmdText, conn);
            insCmd.Parameters.Add("@COURSE_ID", SqlDbType.VarChar);
            insCmd.Parameters.Add("@COURSE_NAME", SqlDbType.VarChar);
            insCmd.Parameters.Add("@COURSE_NO", SqlDbType.VarChar);
            insCmd.Parameters.Add("@BEGIN_DATE", SqlDbType.DateTime);
            insCmd.Parameters.Add("@END_DATE", SqlDbType.DateTime);
            insCmd.Parameters.Add("@CREATER", SqlDbType.VarChar);

            da.InsertCommand = insCmd;  // da is a data adapter

 

However, as I use the preceding adapter to update the underlying database which in fact is based on a disconnected DataRow, an exception is thrown:

      The parameterized query '(@COURSE_ID varchar(8000),@COURSE_NAME varchar(8000),@COURSE_NO ' expects the parameter '@COURSE_ID', which was not supplied.

The code I update the database is as follows:

      DataRow newRow = sourceTable.NewRow();  //sourceTable is a DataTable whose data rows are populated with da (SqlDataAdpater) in the preceding code

      // Populating the newRow

      Hashtable newValues = new Hashtable();

      .....................

            foreach (DictionaryEntry entry in newValues)
            {
                // entry.Key is identical to a column name in the newRow
                newRow[(string)entry.Key] =
                    (entry.Value == null ? DBNull.Value : entry.Value);
            }

            sourceTable.Rows.Add(newRow);

            adapter.SelectCommand.Connection.Open();

            adapter.Update(sourceTable);  // Exception is thrown here

            adapter.SelectCommand.Connection.Close();

 

Please give me some directions to debug. It seems that the values of Columns withn DataRow cannot be fetched into the corresponding adapter.InsertCommand.Parameters by the adpater. (As I use SqlCommandBuilder to automatically generate insert command, the code above wroks rightly.)

Thanks a million.

Ricky.