Help with Read Array from SQL Server

Hello im learning on Supermike Source ,
There is Function calling getSingleArray But i can see it only Return first row of data
i want read an normal Array in C# its really hard :D
i hope someone can help me
Here's my code but its dont return anything

Code:

var dt = sqlCon.GetDataTable($"SELECT id,Title FROM {FilterMain.SUP_DB}.dbo.Titles where CharName = '{Program.Plis(this.sql_charname)}'");

Code:

public static List<string> GetDataTable(string query)
        {
            if (sqlCon.con.State == ConnectionState.Open)
            {
                SqlDataAdapter SqlAD = new SqlDataAdapter();
                SqlAD.SelectCommand = new SqlCommand(query, con);
                DataSet ds = new DataSet();
                SqlAD.Fill(ds);

                DataTable dt = ds.Tables[0];
                if (dt.Rows.Count != 0)
                {
                    var list = new List<string>();
                    for (var i = 0 ; i < dt.Rows.Count;i++)
                    {
                        list.Add(dt.Rows[i].Field<string>(0));
                        Console.WriteLine(i);
                    }
                    return list;
                }


            }
            else
            {
                sqlCon.con.Open();
                sqlCon.GetDataTable(query);
            }
            return null;
        }