PostgreSQL object datatype

[pykie101]

Hi,

I'm having a problem, I'm using PostgreSQL V8.3.3-1, Npgsql and Visual studio 2008 c#.

I'm passed a dictionary of key, value (key been a string, value been an object). The code works fine with key and value both been strings but postgresql doesn't seem to like it when the value is an object. How can I correct my code to work when passed an object? I realise that rowsaffected is currently only storing the first value, that's fine. I just want to be able to run a query using an object datatype for now.

current error is: "InvalidCastException is unhandled by user code"

sql is a query

"SELECT username FROM users WHERE age = :Value1"

        public static string GetSql(string sql, Dictionary<string, object> d)
        {
            string connection = System.Configuration.ConfigurationManager.ConnectionStrings["POSTGRESQL_LOCAL"].ConnectionString;
 
            using (NpgsqlConnection conn = new NpgsqlConnection(connection))
            {
                conn.Open();
                using (NpgsqlCommand command = new NpgsqlCommand(sql, conn))
                {
                    int i = 0;
 
                    foreach (KeyValuePair<string, object> kvp in d)
                    {
                        command.Parameters.Add(new NpgsqlParameter(kvp.Key, DbType.Object));
                        command.Parameters[i].Value = kvp.Value;
                        i++;
                    }
                    string rowsaffected = "error: No data";
                    using (NpgsqlDataReader dr = command.ExecuteReader())
                    {
                        while (dr.Read())
                        {
                            rowsaffected = dr[0].ToString();
                        }
                    }
 
                    conn.Close();
                    return rowsaffected;
 
                }
 
            }
 
        }

I hope I placed this on the correct forum. Most of the code is c# but I feel the problem lies with Postgresql...

Thanks