Save in a variable and multiply double value query result C#/MySql -

i'm trying save unique value resulting query double variable, since same stored in database double, can later able multiply counter, following code:

 public partial class coronaclaracant : form  {     private int conteocliks = 0;     private string producto = "coronaclara";     private double precio;      public coronaclaracant()     {         initializecomponent();       }      private void coronaclara_click(object sender, eventargs e)     {         mysqlconnection conn = new mysqlconnection("server=localhost;database=database;username=root;password=***");          conn.open();          string select = "select precio productos prodnom = '" + producto + "';";          mysqlcommand cmd = new mysqlcommand(select, conn);         double result = cmd.executenonquery();         conteocliks++;         precio = result;           double total = (precio * conteocliks);           lblcantidad.text = conteocliks.tostring();         lblprecio.text = precio.tostring();          lbltotal.text = total.tostring();     } } 

so far i've been getting negative values:

i'm guessing because executenonquery, haven't been able assign double value executescalar method, , i'm not sure if there other parameters should consider when saving double value variable.

you want select data database , calling executenonquery used insert,update or delete commands.

you need call executereader or if want data in datatable can fill datatable.

sqldatareader rdr = cmd.executereader(); if (rdr.hasrows) {    if (rdr.read())      {       precio = (double)rdr["precio"];     } }