dataAdapter.Update problem

[BobLewiston]

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?

[BobLewiston]

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

System.Runtime.InteropServices.ExternalException

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

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