I wrote a general class to insert, update and delete records in ado.net SQL db. I used the following method to select (populate my gridview) but a dictionary is not a good why to do what I need:

private Dictionary<string,string> SelectAll(string ConnectString)

    {
     Dictionary<string,string> coolPeople = new Dictionary<string,string>();

      SqlConnection cn = new SqlConnection(ConnectString);

      cn.Open();

      SqlCommand cmd;


      string sql = “Select * From CoolPeople“;

      try

      {

        cmd = new SqlCommand(sql, cn);
    SqlDataReader reader = cmd.ExecuteReader();
     While(reader.Read())
    {
        coolPeople.Add(reader["firstname"].ToString(),reader["lastname"].ToString());
    }

    reader.Close();
      
      }

      catch (SqlException sqlexception)

      {

        MessageBox.Show(sqlexception.Message, “Oh Crap.”

          , MessageBoxButtons.OK, MessageBoxIcon.Error);

      }

      catch (Exception ex)

      {

        MessageBox.Show(ex.Message, “Oh Crap.”

          , MessageBoxButtons.OK, MessageBoxIcon.Error);

      }

      finally

      {

        cn.Close();

      }
return coolPeople;

    }

I need to display three columns, but the dictionary only return two.

Why don't you have class called Person with three properties.

then have something like this.

List<Person> coolPeople=new List<Person>();

then in your while loop

Person p=new Person();

//set the person properties

 //add the person to the list

return the list