hi how to insert multiple records into database from listbox?

public void SavValues()
    {
        SqlConnection connectionSql = new SqlConnection("Data Source=(local);Integrated Security=sspi");
        SqlCommand commandSql = new SqlCommand();
        commandSql.Connection = connectionSql;
        commandSql.CommandText = "INSERT INTO dbo.Employee (EmployeeName) VALUES (@employeeName)";
        commandSql.Parameters.Add("@employeeName");
        try
        {
            connectionSql.Open();
            for (int indexCounter = 0; indexCounter < listBoxEmployeeName.Items.Count; indexCounter++)
            {
                commandSql.Parameters["employeeName"].Value = listBoxEmployeeName.Items[indexCounter].Text;
                commandSql.ExecuteNonQuery();
            }
            connectionSql.Close();
        }
        catch (Exception exceptionMessage)
        {
            //show error message
        }
        finally
        {
            commandSql.Dispose();
            connectionSql.Close();
            connectionSql.Dispose();
        }
    }