先到网上下载PostgreSql.Data.PostgreSqlClient.dll
然后添加引用,使用命名空间

using PostgreSql.Data.PostgreSqlClient;                  string connectString = @"Server=localhost;Database=postgres;User ID=arwen;Password=arwen";                 PgConnection conn = new PgConnection(connectString);                 conn.Open();                 PgCommand cmd = conn.CreateCommand();                 cmd.CommandText = "select * from test";                 cmd.CommandType = CommandType.Text;                 using (PgDataReader reader = cmd.ExecuteReader())                 {                     while (reader.Read())                         Console.WriteLine(reader[0].ToString());                 }