dataAdapter.Update problem

[BobLewiston]

I can read in an SQL table ("Person.Contac t") 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?

[BobLewiston]

On the off-chance that this will help, this is the exact kind of exception that's occurring:

System.Runtime. InteropServices .ExternalExcept ion

Are there any other properties of the Exception class besides Message and StackTrace that might help me figure this out?

[code green]

You are using SQL variables that have not been declared.

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

Even if they had been declared they would be empty anyway.