CODEWITHSUNDEEP
c#postgresql.net-coretype-conversionrazor-pages
anonD
anonD

Reputation: 47

Can't convert DateTime to string in C#

Hi i'm trying to make a reservation page. If someone makes a reservation that date gets saved in the database and will also be showed on their page. The type of the column 'dayid' is date in postgresql. In razor pages C# i used the type DateTime for variable Dayid. I need to convert the dayid value from database to a string. But i don't know how to solve this error: "No overload for method 'ToString' takes 1 arguments" Here is the code

public List<ReservationModel> ShowReservation()
        {
            var cs = Database.Database.Connector();
            List<ReservationModel> res = new List<ReservationModel>();
            using var con = new NpgsqlConnection(cs);
            {
                string query = "Select dayid, locationid FROM reservation";
                using NpgsqlCommand cmd = new NpgsqlCommand(query, con);
                {
                    cmd.Connection = con;
                    con.Open();
                    using (NpgsqlDataReader dr = cmd.ExecuteReader())
                    {
                        while (dr.Read())
                        {
                            res.Add(new ReservationModel { Dayid = dr["dayid"].ToString("MM/dd/yyyy"), Locationid = dr["locationid"].ToString() });
                        }
                    }
                    
                    con.Close();
                }
            }


            return res;
        }

Upvotes: 1

Views: 851

Answers (1)

Jon Skeet
Jon Skeet

Reputation: 1500893

The compile-time type of the NpgsqlDataReader indexer is just object, and the object.ToString() method is parameterless. You need an expression of type DateTime to call the ToString overload that you want.

You could cast to DateTime instead:

while (dr.Read())
{
    res.Add(new ReservationModel
    {
        Dayid = ((DateTime) dr["dayid"]).ToString("MM/dd/yyyy"),
        Locationid = dr["locationid"].ToString() 
    });
}

(Or find the column index and call dr.GetDateTime(...).)

However, I'd encourage you to change your model (ReservationModel) to keep the value as a DateTime instead of converting it to a string at this point anyway. In general, it's a good idea to keep data in its most natural data type for as much of the time as possible, only converting it to/from text at boundaries.

Upvotes: 5

Related Questions