dataAdapter.Update problem

I can read in an SQL table ("Person.Contact") from AdventureWorks and step through it one row at a time, but when I try to save a record, either one I'm inserting or one I'm editting, I get the following exception:

 

Incorrect syntax near ','. Must declare scalar variable "@ContactID".

 

Here's the code:

 

        private void btnSave_Click (object sender, EventArgs e)

        {

            DataRow row = dataTable.Rows [currentRecord];

            row.BeginEdit ();

 

            // get data from input TextBoxes

            row ["ContactID"]    = txtContactID.Text;

            row ["FirstName"]    = txtFirstName.Text;

            row ["LastName"]     = txtLastName.Text;

            row ["Phone"]        = txtPhone.Text;

            row ["EmailAddress"] = txtEmailAddress.Text;

 

            row.EndEdit ();

 

            try { dataAdapter.Update (dataSet, "Person.Contact"); }        // HERE'S THE PROBLEM

            catch (Exception exc) { MessageBox.Show (exc.Message); }

 

            dataSet.AcceptChanges ();

        }

 

I don't think the problem is with inializing the SQL commands. Here's the code for that (shown without the "Delete SQL Command" section). No exceptions are thrown.

 

        private void InitializeCommands ()

        {

            // Preparing Insert SQL Command

            try

            {

                dataAdapter.InsertCommand = conn.CreateCommand ();

                dataAdapter.InsertCommand.CommandText =

                    "INSERT INTO Person.Contact (ContactID, FirstName, LastName, Phone,

                    EmailAddress) VALUES (@ContactID, @FirstName, @LastName, @Phone,

                    @EmailAddress)";

                AddParams (dataAdapter.InsertCommand, "ContactID, FirstName, LastName,

                    Phone, EmailAddress");

            }

            catch (Exception exc) { MessageBox.Show (exc.Message, "InsertCommand"); }

 

            // Preparing Update SQL Command

            try

            {

                dataAdapter.UpdateCommand = conn.CreateCommand ();

                dataAdapter.UpdateCommand.CommandText =

                    "UPDATE Person.Contact SET FirstName = @FirstName, LastName =

                    @LastName, Phone = @Phone, EmailAddress = @EmailAddress WHERE

                    ContactID = @ContactID";

                AddParams (dataAdapter.UpdateCommand, "ContactID, FirstName, LastName,

                    Phone, EmailAddress");

            }

            catch (Exception exc) { MessageBox.Show (exc.Message, "UpdateCommand"); }

        }

 

        // add column name(s) supplied in params (prefixed with '@') into Parameters collection of

        // SqlCommand class

        // SqlDbType.Char: type of parameter, 0: size of parameter, column: column name

        private void AddParams (SqlCommand cmd, params string [ ] columns)

        {

            foreach (string column in columns)

                cmd.Parameters.Add ("@" + column, SqlDbType.Char, 0, column);

        }

}

 

Any ideas?