Combobox_Concat

        //!============================================
        //!METHOD FOR POPULATING COMBOBOX USING A CLASS
        //!============================================
        void FillCombobox()
        {
            List<Trades> trader = new List<Trades>();

            using (SqlConnection con = new(connectionString))
            {
                if (con.State == ConnectionState.Closed)
                    con.Open();

                using (SqlDataAdapter da = new SqlDataAdapter("AllTrades", con))
                {
                    da.SelectCommand.CommandType = CommandType.StoredProcedure;

                    using (var reader = da.SelectCommand.ExecuteReader())
                    {
                        while (reader.Read())
                        {
                            Trades trades = new Trades
                            {
                                Id = reader.GetInt32(0),
                                tradeID = reader.GetString(1),
                                firstName = reader.GetString(2),
                                lastName = reader.GetString(3),
                                trade = reader.GetString(4),
                                contactNumber = reader.GetString(5),
                                email = reader.GetString(6),
                            };
                            trader.Add(trades);
                        }
                    }

                    cbxFindTrader.DisplayMember = "fullName";//public string fullDetails => $"{firstName} {lastName} {trade}";
                    cbxFindTrader.ValueMember = "Id";
                    cbxFindTrader.DataSource = trader;
                }
            }
        }

        //!=================================
        //!METHOD FOR POPULATING COMBOBOX SP
        //!=================================
        void PopulateTradesCombobox()
        {
            using (SqlConnection con = new(connectionString))
            {

                if (con.State == ConnectionState.Closed)
                    con.Open();

                using (SqlDataAdapter da = new SqlDataAdapter("AllTrades", con))

                {
                    da.SelectCommand.CommandType = CommandType.StoredProcedure;

                    DataTable dtbl = new("AssociatedTrades");
                    da.Fill(dtbl);


                    cbxFindTrader.DisplayMember = "fullName";
                    cbxFindTrader.ValueMember = "Id";
                    DataRow topRow = dtbl.NewRow();
                    topRow[0] = 0;
                    topRow[0] = "--Select--";
                    dtbl.Rows.InsertAt(topRow, 0);
                    cbxFindTrader.DataSource = dtbl;
                }
            }
        }

        //!=====
        //!QUERY
        //!=====

ALTER PROC [dbo].[AllTrades]
--@Name nvarchar(50)

as
SELECT
    RTRIM(LTRIM(
        CONCAT(

            COALESCE(firstName + ' ', '')
            ,COALESCE(lastName + '', '')
            ,COALESCE(trade + '', '')
        )
    )) AS fullName

FROM AssociatedTrades